linux/arch/x86/kvm/cpuid.c

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/*
* Kernel-based Virtual Machine driver for Linux
* cpuid support routines
*
* derived from arch/x86/kvm/x86.c
*
* Copyright 2011 Red Hat, Inc. and/or its affiliates.
* Copyright IBM Corporation, 2008
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include <linux/kvm_host.h>
x86/kvm: Audit and remove any unnecessary uses of module.h Historically a lot of these existed because we did not have a distinction between what was modular code and what was providing support to modules via EXPORT_SYMBOL and friends. That changed when we forked out support for the latter into the export.h file. This means we should be able to reduce the usage of module.h in code that is obj-y Makefile or bool Kconfig. In the case of kvm where it is modular, we can extend that to also include files that are building basic support functionality but not related to loading or registering the final module; such files also have no need whatsoever for module.h The advantage in removing such instances is that module.h itself sources about 15 other headers; adding significantly to what we feed cpp, and it can obscure what headers we are effectively using. Since module.h was the source for init.h (for __init) and for export.h (for EXPORT_SYMBOL) we consider each instance for the presence of either and replace as needed. Several instances got replaced with moduleparam.h since that was really all that was required for those particular files. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kvm@vger.kernel.org Link: http://lkml.kernel.org/r/20160714001901.31603-8-paul.gortmaker@windriver.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-14 08:19:00 +08:00
#include <linux/export.h>
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
#include <linux/sched/stat.h>
#include <asm/processor.h>
#include <asm/user.h>
#include <asm/fpu/xstate.h>
#include "cpuid.h"
#include "lapic.h"
#include "mmu.h"
#include "trace.h"
#include "pmu.h"
static u32 xstate_required_size(u64 xstate_bv, bool compacted)
{
int feature_bit = 0;
u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
x86/fpu: Rename XSAVE macros There are two concepts that have some confusing naming: 1. Extended State Component numbers (currently called XFEATURE_BIT_*) 2. Extended State Component masks (currently called XSTATE_*) The numbers are (currently) from 0-9. State component 3 is the bounds registers for MPX, for instance. But when we want to enable "state component 3", we go set a bit in XCR0. The bit we set is 1<<3. We can check to see if a state component feature is enabled by looking at its bit. The current 'xfeature_bit's are at best xfeature bit _numbers_. Calling them bits is at best inconsistent with ending the enum list with 'XFEATURES_NR_MAX'. This patch renames the enum to be 'xfeature'. These also happen to be what the Intel documentation calls a "state component". We also want to differentiate these from the "XSTATE_*" macros. The "XSTATE_*" macros are a mask, and we rename them to match. These macros are reasonably widely used so this patch is a wee bit big, but this really is just a rename. The only non-mechanical part of this is the s/XSTATE_EXTEND_MASK/XFEATURE_MASK_EXTEND/ We need a better name for it, but that's another patch. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: dave@sr71.net Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20150902233126.38653250@viggo.jf.intel.com [ Ported to v4.3-rc1. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-03 07:31:26 +08:00
xstate_bv &= XFEATURE_MASK_EXTEND;
while (xstate_bv) {
if (xstate_bv & 0x1) {
u32 eax, ebx, ecx, edx, offset;
cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx);
offset = compacted ? ret : ebx;
ret = max(ret, offset + eax);
}
xstate_bv >>= 1;
feature_bit++;
}
return ret;
}
bool kvm_mpx_supported(void)
{
return ((host_xcr0 & (XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR))
&& kvm_x86_ops->mpx_supported());
}
EXPORT_SYMBOL_GPL(kvm_mpx_supported);
u64 kvm_supported_xcr0(void)
{
u64 xcr0 = KVM_SUPPORTED_XCR0 & host_xcr0;
if (!kvm_mpx_supported())
x86/fpu: Rename XSAVE macros There are two concepts that have some confusing naming: 1. Extended State Component numbers (currently called XFEATURE_BIT_*) 2. Extended State Component masks (currently called XSTATE_*) The numbers are (currently) from 0-9. State component 3 is the bounds registers for MPX, for instance. But when we want to enable "state component 3", we go set a bit in XCR0. The bit we set is 1<<3. We can check to see if a state component feature is enabled by looking at its bit. The current 'xfeature_bit's are at best xfeature bit _numbers_. Calling them bits is at best inconsistent with ending the enum list with 'XFEATURES_NR_MAX'. This patch renames the enum to be 'xfeature'. These also happen to be what the Intel documentation calls a "state component". We also want to differentiate these from the "XSTATE_*" macros. The "XSTATE_*" macros are a mask, and we rename them to match. These macros are reasonably widely used so this patch is a wee bit big, but this really is just a rename. The only non-mechanical part of this is the s/XSTATE_EXTEND_MASK/XFEATURE_MASK_EXTEND/ We need a better name for it, but that's another patch. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: dave@sr71.net Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20150902233126.38653250@viggo.jf.intel.com [ Ported to v4.3-rc1. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-03 07:31:26 +08:00
xcr0 &= ~(XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR);
return xcr0;
}
#define F(x) bit(X86_FEATURE_##x)
/* For scattered features from cpufeatures.h; we currently expose none */
#define KF(x) bit(KVM_CPUID_BIT_##x)
int kvm_update_cpuid(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
struct kvm_lapic *apic = vcpu->arch.apic;
best = kvm_find_cpuid_entry(vcpu, 1, 0);
if (!best)
return 0;
/* Update OSXSAVE bit */
if (boot_cpu_has(X86_FEATURE_XSAVE) && best->function == 0x1) {
best->ecx &= ~F(OSXSAVE);
if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
best->ecx |= F(OSXSAVE);
}
best->edx &= ~F(APIC);
if (vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE)
best->edx |= F(APIC);
if (apic) {
if (best->ecx & F(TSC_DEADLINE_TIMER))
apic->lapic_timer.timer_mode_mask = 3 << 17;
else
apic->lapic_timer.timer_mode_mask = 1 << 17;
}
best = kvm_find_cpuid_entry(vcpu, 7, 0);
if (best) {
/* Update OSPKE bit */
if (boot_cpu_has(X86_FEATURE_PKU) && best->function == 0x7) {
best->ecx &= ~F(OSPKE);
if (kvm_read_cr4_bits(vcpu, X86_CR4_PKE))
best->ecx |= F(OSPKE);
}
}
best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
if (!best) {
vcpu->arch.guest_supported_xcr0 = 0;
vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
} else {
vcpu->arch.guest_supported_xcr0 =
(best->eax | ((u64)best->edx << 32)) &
kvm_supported_xcr0();
vcpu->arch.guest_xstate_size = best->ebx =
xstate_required_size(vcpu->arch.xcr0, false);
}
best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
if (best && (best->eax & (F(XSAVES) | F(XSAVEC))))
best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
/*
* The existing code assumes virtual address is 48-bit or 57-bit in the
* canonical address checks; exit if it is ever changed.
*/
best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
if (best) {
int vaddr_bits = (best->eax & 0xff00) >> 8;
if (vaddr_bits != 48 && vaddr_bits != 57 && vaddr_bits != 0)
return -EINVAL;
}
best = kvm_find_cpuid_entry(vcpu, KVM_CPUID_FEATURES, 0);
if (kvm_hlt_in_guest(vcpu->kvm) && best &&
(best->eax & (1 << KVM_FEATURE_PV_UNHALT)))
best->eax &= ~(1 << KVM_FEATURE_PV_UNHALT);
/* Update physical-address width */
vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
kvm_mmu_reset_context(vcpu);
kvm_pmu_refresh(vcpu);
return 0;
}
static int is_efer_nx(void)
{
unsigned long long efer = 0;
rdmsrl_safe(MSR_EFER, &efer);
return efer & EFER_NX;
}
static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
{
int i;
struct kvm_cpuid_entry2 *e, *entry;
entry = NULL;
for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
e = &vcpu->arch.cpuid_entries[i];
if (e->function == 0x80000001) {
entry = e;
break;
}
}
if (entry && (entry->edx & F(NX)) && !is_efer_nx()) {
entry->edx &= ~F(NX);
printk(KERN_INFO "kvm: guest NX capability removed\n");
}
}
int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
if (!best || best->eax < 0x80000008)
goto not_found;
best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
if (best)
return best->eax & 0xff;
not_found:
return 36;
}
EXPORT_SYMBOL_GPL(cpuid_query_maxphyaddr);
/* when an old userspace process fills a new kernel module */
int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
struct kvm_cpuid *cpuid,
struct kvm_cpuid_entry __user *entries)
{
int r, i;
struct kvm_cpuid_entry *cpuid_entries = NULL;
r = -E2BIG;
if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
goto out;
r = -ENOMEM;
if (cpuid->nent) {
treewide: Use array_size() in vmalloc() The vmalloc() function has no 2-factor argument form, so multiplication factors need to be wrapped in array_size(). This patch replaces cases of: vmalloc(a * b) with: vmalloc(array_size(a, b)) as well as handling cases of: vmalloc(a * b * c) with: vmalloc(array3_size(a, b, c)) This does, however, attempt to ignore constant size factors like: vmalloc(4 * 1024) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( vmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | vmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( vmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(u8) * COUNT + COUNT , ...) | vmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | vmalloc( - sizeof(char) * COUNT + COUNT , ...) | vmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( vmalloc( - sizeof(TYPE) * (COUNT_ID) + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT_ID + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT_CONST + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vmalloc( - sizeof(THING) * (COUNT_ID) + array_size(COUNT_ID, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT_ID + array_size(COUNT_ID, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT_CONST + array_size(COUNT_CONST, sizeof(THING)) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ vmalloc( - SIZE * COUNT + array_size(COUNT, SIZE) , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( vmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( vmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( vmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( vmalloc(C1 * C2 * C3, ...) | vmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants. @@ expression E1, E2; constant C1, C2; @@ ( vmalloc(C1 * C2, ...) | vmalloc( - E1 * E2 + array_size(E1, E2) , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-13 05:27:11 +08:00
cpuid_entries =
vmalloc(array_size(sizeof(struct kvm_cpuid_entry),
cpuid->nent));
if (!cpuid_entries)
goto out;
r = -EFAULT;
if (copy_from_user(cpuid_entries, entries,
cpuid->nent * sizeof(struct kvm_cpuid_entry)))
goto out;
}
for (i = 0; i < cpuid->nent; i++) {
vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
vcpu->arch.cpuid_entries[i].index = 0;
vcpu->arch.cpuid_entries[i].flags = 0;
vcpu->arch.cpuid_entries[i].padding[0] = 0;
vcpu->arch.cpuid_entries[i].padding[1] = 0;
vcpu->arch.cpuid_entries[i].padding[2] = 0;
}
vcpu->arch.cpuid_nent = cpuid->nent;
cpuid_fix_nx_cap(vcpu);
kvm_apic_set_version(vcpu);
kvm_x86_ops->cpuid_update(vcpu);
r = kvm_update_cpuid(vcpu);
out:
vfree(cpuid_entries);
return r;
}
int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
struct kvm_cpuid2 *cpuid,
struct kvm_cpuid_entry2 __user *entries)
{
int r;
r = -E2BIG;
if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
goto out;
r = -EFAULT;
if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
goto out;
vcpu->arch.cpuid_nent = cpuid->nent;
kvm_apic_set_version(vcpu);
kvm_x86_ops->cpuid_update(vcpu);
r = kvm_update_cpuid(vcpu);
out:
return r;
}
int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
struct kvm_cpuid2 *cpuid,
struct kvm_cpuid_entry2 __user *entries)
{
int r;
r = -E2BIG;
if (cpuid->nent < vcpu->arch.cpuid_nent)
goto out;
r = -EFAULT;
if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
goto out;
return 0;
out:
cpuid->nent = vcpu->arch.cpuid_nent;
return r;
}
static void cpuid_mask(u32 *word, int wordnum)
{
*word &= boot_cpu_data.x86_capability[wordnum];
}
static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
u32 index)
{
entry->function = function;
entry->index = index;
cpuid_count(entry->function, entry->index,
&entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
entry->flags = 0;
}
static int __do_cpuid_ent_emulated(struct kvm_cpuid_entry2 *entry,
u32 func, u32 index, int *nent, int maxnent)
{
switch (func) {
case 0:
entry->eax = 7;
++*nent;
break;
case 1:
entry->ecx = F(MOVBE);
++*nent;
break;
case 7:
entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
if (index == 0)
entry->ecx = F(RDPID);
++*nent;
default:
break;
}
entry->function = func;
entry->index = index;
return 0;
}
static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
u32 index, int *nent, int maxnent)
{
int r;
unsigned f_nx = is_efer_nx() ? F(NX) : 0;
#ifdef CONFIG_X86_64
unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
? F(GBPAGES) : 0;
unsigned f_lm = F(LM);
#else
unsigned f_gbpages = 0;
unsigned f_lm = 0;
#endif
unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
unsigned f_mpx = kvm_mpx_supported() ? F(MPX) : 0;
unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
unsigned f_umip = kvm_x86_ops->umip_emulated() ? F(UMIP) : 0;
/* cpuid 1.edx */
const u32 kvm_cpuid_1_edx_x86_features =
F(FPU) | F(VME) | F(DE) | F(PSE) |
F(TSC) | F(MSR) | F(PAE) | F(MCE) |
F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLUSH) |
0 /* Reserved, DS, ACPI */ | F(MMX) |
F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
0 /* HTT, TM, Reserved, PBE */;
/* cpuid 0x80000001.edx */
const u32 kvm_cpuid_8000_0001_edx_x86_features =
F(FPU) | F(VME) | F(DE) | F(PSE) |
F(TSC) | F(MSR) | F(PAE) | F(MCE) |
F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
F(PAT) | F(PSE36) | 0 /* Reserved */ |
f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
/* cpuid 1.ecx */
const u32 kvm_cpuid_1_ecx_x86_features =
/* NOTE: MONITOR (and MWAIT) are emulated as NOP,
* but *not* advertised to guests via CPUID ! */
F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
0 /* DS-CPL, VMX, SMX, EST */ |
0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
F(F16C) | F(RDRAND);
/* cpuid 0x80000001.ecx */
const u32 kvm_cpuid_8000_0001_ecx_x86_features =
F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM) |
F(TOPOEXT) | F(PERFCTR_CORE);
KVM/x86: Add IBPB support The Indirect Branch Predictor Barrier (IBPB) is an indirect branch control mechanism. It keeps earlier branches from influencing later ones. Unlike IBRS and STIBP, IBPB does not define a new mode of operation. It's a command that ensures predicted branch targets aren't used after the barrier. Although IBRS and IBPB are enumerated by the same CPUID enumeration, IBPB is very different. IBPB helps mitigate against three potential attacks: * Mitigate guests from being attacked by other guests. - This is addressed by issing IBPB when we do a guest switch. * Mitigate attacks from guest/ring3->host/ring3. These would require a IBPB during context switch in host, or after VMEXIT. The host process has two ways to mitigate - Either it can be compiled with retpoline - If its going through context switch, and has set !dumpable then there is a IBPB in that path. (Tim's patch: https://patchwork.kernel.org/patch/10192871) - The case where after a VMEXIT you return back to Qemu might make Qemu attackable from guest when Qemu isn't compiled with retpoline. There are issues reported when doing IBPB on every VMEXIT that resulted in some tsc calibration woes in guest. * Mitigate guest/ring0->host/ring0 attacks. When host kernel is using retpoline it is safe against these attacks. If host kernel isn't using retpoline we might need to do a IBPB flush on every VMEXIT. Even when using retpoline for indirect calls, in certain conditions 'ret' can use the BTB on Skylake-era CPUs. There are other mitigations available like RSB stuffing/clearing. * IBPB is issued only for SVM during svm_free_vcpu(). VMX has a vmclear and SVM doesn't. Follow discussion here: https://lkml.org/lkml/2018/1/15/146 Please refer to the following spec for more details on the enumeration and control. Refer here to get documentation about mitigations. https://software.intel.com/en-us/side-channel-security-support [peterz: rebase and changelog rewrite] [karahmed: - rebase - vmx: expose PRED_CMD if guest has it in CPUID - svm: only pass through IBPB if guest has it in CPUID - vmx: support !cpu_has_vmx_msr_bitmap()] - vmx: support nested] [dwmw2: Expose CPUID bit too (AMD IBPB only for now as we lack IBRS) PRED_CMD is a write-only MSR] Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: kvm@vger.kernel.org Cc: Asit Mallick <asit.k.mallick@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Jun Nakajima <jun.nakajima@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/1515720739-43819-6-git-send-email-ashok.raj@intel.com Link: https://lkml.kernel.org/r/1517522386-18410-3-git-send-email-karahmed@amazon.de
2018-02-02 05:59:43 +08:00
/* cpuid 0x80000008.ebx */
const u32 kvm_cpuid_8000_0008_ebx_x86_features =
F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) |
F(AMD_SSB_NO);
KVM/x86: Add IBPB support The Indirect Branch Predictor Barrier (IBPB) is an indirect branch control mechanism. It keeps earlier branches from influencing later ones. Unlike IBRS and STIBP, IBPB does not define a new mode of operation. It's a command that ensures predicted branch targets aren't used after the barrier. Although IBRS and IBPB are enumerated by the same CPUID enumeration, IBPB is very different. IBPB helps mitigate against three potential attacks: * Mitigate guests from being attacked by other guests. - This is addressed by issing IBPB when we do a guest switch. * Mitigate attacks from guest/ring3->host/ring3. These would require a IBPB during context switch in host, or after VMEXIT. The host process has two ways to mitigate - Either it can be compiled with retpoline - If its going through context switch, and has set !dumpable then there is a IBPB in that path. (Tim's patch: https://patchwork.kernel.org/patch/10192871) - The case where after a VMEXIT you return back to Qemu might make Qemu attackable from guest when Qemu isn't compiled with retpoline. There are issues reported when doing IBPB on every VMEXIT that resulted in some tsc calibration woes in guest. * Mitigate guest/ring0->host/ring0 attacks. When host kernel is using retpoline it is safe against these attacks. If host kernel isn't using retpoline we might need to do a IBPB flush on every VMEXIT. Even when using retpoline for indirect calls, in certain conditions 'ret' can use the BTB on Skylake-era CPUs. There are other mitigations available like RSB stuffing/clearing. * IBPB is issued only for SVM during svm_free_vcpu(). VMX has a vmclear and SVM doesn't. Follow discussion here: https://lkml.org/lkml/2018/1/15/146 Please refer to the following spec for more details on the enumeration and control. Refer here to get documentation about mitigations. https://software.intel.com/en-us/side-channel-security-support [peterz: rebase and changelog rewrite] [karahmed: - rebase - vmx: expose PRED_CMD if guest has it in CPUID - svm: only pass through IBPB if guest has it in CPUID - vmx: support !cpu_has_vmx_msr_bitmap()] - vmx: support nested] [dwmw2: Expose CPUID bit too (AMD IBPB only for now as we lack IBRS) PRED_CMD is a write-only MSR] Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: kvm@vger.kernel.org Cc: Asit Mallick <asit.k.mallick@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Jun Nakajima <jun.nakajima@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/1515720739-43819-6-git-send-email-ashok.raj@intel.com Link: https://lkml.kernel.org/r/1517522386-18410-3-git-send-email-karahmed@amazon.de
2018-02-02 05:59:43 +08:00
/* cpuid 0xC0000001.edx */
const u32 kvm_cpuid_C000_0001_edx_x86_features =
F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
F(PMM) | F(PMM_EN);
/* cpuid 7.0.ebx */
const u32 kvm_cpuid_7_0_ebx_x86_features =
F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
F(ADX) | F(SMAP) | F(AVX512IFMA) | F(AVX512F) | F(AVX512PF) |
F(AVX512ER) | F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) |
F(SHA_NI) | F(AVX512BW) | F(AVX512VL);
/* cpuid 0xD.1.eax */
const u32 kvm_cpuid_D_1_eax_x86_features =
F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves;
/* cpuid 7.0.ecx*/
const u32 kvm_cpuid_7_0_ecx_x86_features =
F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ |
F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
F(CLDEMOTE);
/* cpuid 7.0.edx*/
const u32 kvm_cpuid_7_0_edx_x86_features =
F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES);
/* all calls to cpuid_count() should be made on the same cpu */
get_cpu();
r = -E2BIG;
if (*nent >= maxnent)
goto out;
do_cpuid_1_ent(entry, function, index);
++*nent;
switch (function) {
case 0:
entry->eax = min(entry->eax, (u32)0xd);
break;
case 1:
entry->edx &= kvm_cpuid_1_edx_x86_features;
cpuid_mask(&entry->edx, CPUID_1_EDX);
entry->ecx &= kvm_cpuid_1_ecx_x86_features;
cpuid_mask(&entry->ecx, CPUID_1_ECX);
/* we support x2apic emulation even if host does not support
* it since we emulate x2apic in software */
entry->ecx |= F(X2APIC);
break;
/* function 2 entries are STATEFUL. That is, repeated cpuid commands
* may return different values. This forces us to get_cpu() before
* issuing the first command, and also to emulate this annoying behavior
* in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
case 2: {
int t, times = entry->eax & 0xff;
entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
for (t = 1; t < times; ++t) {
if (*nent >= maxnent)
goto out;
do_cpuid_1_ent(&entry[t], function, 0);
entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
++*nent;
}
break;
}
/* function 4 has additional index. */
case 4: {
int i, cache_type;
entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
/* read more entries until cache_type is zero */
for (i = 1; ; ++i) {
if (*nent >= maxnent)
goto out;
cache_type = entry[i - 1].eax & 0x1f;
if (!cache_type)
break;
do_cpuid_1_ent(&entry[i], function, i);
entry[i].flags |=
KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
++*nent;
}
break;
}
case 6: /* Thermal management */
entry->eax = 0x4; /* allow ARAT */
entry->ebx = 0;
entry->ecx = 0;
entry->edx = 0;
break;
case 7: {
entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
/* Mask ebx against host capability word 9 */
if (index == 0) {
entry->ebx &= kvm_cpuid_7_0_ebx_x86_features;
cpuid_mask(&entry->ebx, CPUID_7_0_EBX);
KVM: x86: Emulate IA32_TSC_ADJUST MSR CPUID.7.0.EBX[1]=1 indicates IA32_TSC_ADJUST MSR 0x3b is supported Basic design is to emulate the MSR by allowing reads and writes to a guest vcpu specific location to store the value of the emulated MSR while adding the value to the vmcs tsc_offset. In this way the IA32_TSC_ADJUST value will be included in all reads to the TSC MSR whether through rdmsr or rdtsc. This is of course as long as the "use TSC counter offsetting" VM-execution control is enabled as well as the IA32_TSC_ADJUST control. However, because hardware will only return the TSC + IA32_TSC_ADJUST + vmsc tsc_offset for a guest process when it does and rdtsc (with the correct settings) the value of our virtualized IA32_TSC_ADJUST must be stored in one of these three locations. The argument against storing it in the actual MSR is performance. This is likely to be seldom used while the save/restore is required on every transition. IA32_TSC_ADJUST was created as a way to solve some issues with writing TSC itself so that is not an option either. The remaining option, defined above as our solution has the problem of returning incorrect vmcs tsc_offset values (unless we intercept and fix, not done here) as mentioned above. However, more problematic is that storing the data in vmcs tsc_offset will have a different semantic effect on the system than does using the actual MSR. This is illustrated in the following example: The hypervisor set the IA32_TSC_ADJUST, then the guest sets it and a guest process performs a rdtsc. In this case the guest process will get TSC + IA32_TSC_ADJUST_hyperviser + vmsc tsc_offset including IA32_TSC_ADJUST_guest. While the total system semantics changed the semantics as seen by the guest do not and hence this will not cause a problem. Signed-off-by: Will Auld <will.auld@intel.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-11-30 04:42:50 +08:00
// TSC_ADJUST is emulated
entry->ebx |= F(TSC_ADJUST);
entry->ecx &= kvm_cpuid_7_0_ecx_x86_features;
cpuid_mask(&entry->ecx, CPUID_7_ECX);
entry->ecx |= f_umip;
/* PKU is not yet implemented for shadow paging. */
if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
entry->ecx &= ~F(PKU);
entry->edx &= kvm_cpuid_7_0_edx_x86_features;
cpuid_mask(&entry->edx, CPUID_7_EDX);
/*
* We emulate ARCH_CAPABILITIES in software even
* if the host doesn't support it.
*/
entry->edx |= F(ARCH_CAPABILITIES);
} else {
entry->ebx = 0;
entry->ecx = 0;
entry->edx = 0;
}
entry->eax = 0;
break;
}
case 9:
break;
case 0xa: { /* Architectural Performance Monitoring */
struct x86_pmu_capability cap;
union cpuid10_eax eax;
union cpuid10_edx edx;
perf_get_x86_pmu_capability(&cap);
/*
* Only support guest architectural pmu on a host
* with architectural pmu.
*/
if (!cap.version)
memset(&cap, 0, sizeof(cap));
eax.split.version_id = min(cap.version, 2);
eax.split.num_counters = cap.num_counters_gp;
eax.split.bit_width = cap.bit_width_gp;
eax.split.mask_length = cap.events_mask_len;
edx.split.num_counters_fixed = cap.num_counters_fixed;
edx.split.bit_width_fixed = cap.bit_width_fixed;
edx.split.reserved = 0;
entry->eax = eax.full;
entry->ebx = cap.events_mask;
entry->ecx = 0;
entry->edx = edx.full;
break;
}
/* function 0xb has additional index. */
case 0xb: {
int i, level_type;
entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
/* read more entries until level_type is zero */
for (i = 1; ; ++i) {
if (*nent >= maxnent)
goto out;
level_type = entry[i - 1].ecx & 0xff00;
if (!level_type)
break;
do_cpuid_1_ent(&entry[i], function, i);
entry[i].flags |=
KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
++*nent;
}
break;
}
case 0xd: {
int idx, i;
u64 supported = kvm_supported_xcr0();
entry->eax &= supported;
entry->ebx = xstate_required_size(supported, false);
entry->ecx = entry->ebx;
entry->edx &= supported >> 32;
entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
if (!supported)
break;
for (idx = 1, i = 1; idx < 64; ++idx) {
u64 mask = ((u64)1 << idx);
if (*nent >= maxnent)
goto out;
do_cpuid_1_ent(&entry[i], function, idx);
if (idx == 1) {
entry[i].eax &= kvm_cpuid_D_1_eax_x86_features;
cpuid_mask(&entry[i].eax, CPUID_D_1_EAX);
entry[i].ebx = 0;
if (entry[i].eax & (F(XSAVES)|F(XSAVEC)))
entry[i].ebx =
xstate_required_size(supported,
true);
} else {
if (entry[i].eax == 0 || !(supported & mask))
continue;
if (WARN_ON_ONCE(entry[i].ecx & 1))
continue;
}
entry[i].ecx = 0;
entry[i].edx = 0;
entry[i].flags |=
KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
++*nent;
++i;
}
break;
}
case KVM_CPUID_SIGNATURE: {
static const char signature[12] = "KVMKVMKVM\0\0";
const u32 *sigptr = (const u32 *)signature;
entry->eax = KVM_CPUID_FEATURES;
entry->ebx = sigptr[0];
entry->ecx = sigptr[1];
entry->edx = sigptr[2];
break;
}
case KVM_CPUID_FEATURES:
entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
(1 << KVM_FEATURE_NOP_IO_DELAY) |
(1 << KVM_FEATURE_CLOCKSOURCE2) |
(1 << KVM_FEATURE_ASYNC_PF) |
(1 << KVM_FEATURE_PV_EOI) |
(1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
(1 << KVM_FEATURE_PV_UNHALT) |
(1 << KVM_FEATURE_PV_TLB_FLUSH) |
KVM: X86: Implement "send IPI" hypercall Using hypercall to send IPIs by one vmexit instead of one by one for xAPIC/x2APIC physical mode and one vmexit per-cluster for x2APIC cluster mode. Intel guest can enter x2apic cluster mode when interrupt remmaping is enabled in qemu, however, latest AMD EPYC still just supports xapic mode which can get great improvement by Exit-less IPIs. This patchset lets a guest send multicast IPIs, with at most 128 destinations per hypercall in 64-bit mode and 64 vCPUs per hypercall in 32-bit mode. Hardware: Xeon Skylake 2.5GHz, 2 sockets, 40 cores, 80 threads, the VM is 80 vCPUs, IPI microbenchmark(https://lkml.org/lkml/2017/12/19/141): x2apic cluster mode, vanilla Dry-run: 0, 2392199 ns Self-IPI: 6907514, 15027589 ns Normal IPI: 223910476, 251301666 ns Broadcast IPI: 0, 9282161150 ns Broadcast lock: 0, 8812934104 ns x2apic cluster mode, pv-ipi Dry-run: 0, 2449341 ns Self-IPI: 6720360, 15028732 ns Normal IPI: 228643307, 255708477 ns Broadcast IPI: 0, 7572293590 ns => 22% performance boost Broadcast lock: 0, 8316124651 ns x2apic physical mode, vanilla Dry-run: 0, 3135933 ns Self-IPI: 8572670, 17901757 ns Normal IPI: 226444334, 255421709 ns Broadcast IPI: 0, 19845070887 ns Broadcast lock: 0, 19827383656 ns x2apic physical mode, pv-ipi Dry-run: 0, 2446381 ns Self-IPI: 6788217, 15021056 ns Normal IPI: 219454441, 249583458 ns Broadcast IPI: 0, 7806540019 ns => 154% performance boost Broadcast lock: 0, 9143618799 ns Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-07-23 14:39:54 +08:00
(1 << KVM_FEATURE_ASYNC_PF_VMEXIT) |
(1 << KVM_FEATURE_PV_SEND_IPI);
if (sched_info_on())
entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
entry->ebx = 0;
entry->ecx = 0;
entry->edx = 0;
break;
case 0x80000000:
entry->eax = min(entry->eax, 0x8000001f);
break;
case 0x80000001:
entry->edx &= kvm_cpuid_8000_0001_edx_x86_features;
cpuid_mask(&entry->edx, CPUID_8000_0001_EDX);
entry->ecx &= kvm_cpuid_8000_0001_ecx_x86_features;
cpuid_mask(&entry->ecx, CPUID_8000_0001_ECX);
break;
case 0x80000007: /* Advanced power management */
/* invariant TSC is CPUID.80000007H:EDX[8] */
entry->edx &= (1 << 8);
/* mask against host */
entry->edx &= boot_cpu_data.x86_power;
entry->eax = entry->ebx = entry->ecx = 0;
break;
case 0x80000008: {
unsigned g_phys_as = (entry->eax >> 16) & 0xff;
unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
unsigned phys_as = entry->eax & 0xff;
if (!g_phys_as)
g_phys_as = phys_as;
entry->eax = g_phys_as | (virt_as << 8);
KVM/x86: Add IBPB support The Indirect Branch Predictor Barrier (IBPB) is an indirect branch control mechanism. It keeps earlier branches from influencing later ones. Unlike IBRS and STIBP, IBPB does not define a new mode of operation. It's a command that ensures predicted branch targets aren't used after the barrier. Although IBRS and IBPB are enumerated by the same CPUID enumeration, IBPB is very different. IBPB helps mitigate against three potential attacks: * Mitigate guests from being attacked by other guests. - This is addressed by issing IBPB when we do a guest switch. * Mitigate attacks from guest/ring3->host/ring3. These would require a IBPB during context switch in host, or after VMEXIT. The host process has two ways to mitigate - Either it can be compiled with retpoline - If its going through context switch, and has set !dumpable then there is a IBPB in that path. (Tim's patch: https://patchwork.kernel.org/patch/10192871) - The case where after a VMEXIT you return back to Qemu might make Qemu attackable from guest when Qemu isn't compiled with retpoline. There are issues reported when doing IBPB on every VMEXIT that resulted in some tsc calibration woes in guest. * Mitigate guest/ring0->host/ring0 attacks. When host kernel is using retpoline it is safe against these attacks. If host kernel isn't using retpoline we might need to do a IBPB flush on every VMEXIT. Even when using retpoline for indirect calls, in certain conditions 'ret' can use the BTB on Skylake-era CPUs. There are other mitigations available like RSB stuffing/clearing. * IBPB is issued only for SVM during svm_free_vcpu(). VMX has a vmclear and SVM doesn't. Follow discussion here: https://lkml.org/lkml/2018/1/15/146 Please refer to the following spec for more details on the enumeration and control. Refer here to get documentation about mitigations. https://software.intel.com/en-us/side-channel-security-support [peterz: rebase and changelog rewrite] [karahmed: - rebase - vmx: expose PRED_CMD if guest has it in CPUID - svm: only pass through IBPB if guest has it in CPUID - vmx: support !cpu_has_vmx_msr_bitmap()] - vmx: support nested] [dwmw2: Expose CPUID bit too (AMD IBPB only for now as we lack IBRS) PRED_CMD is a write-only MSR] Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: kvm@vger.kernel.org Cc: Asit Mallick <asit.k.mallick@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Jun Nakajima <jun.nakajima@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/1515720739-43819-6-git-send-email-ashok.raj@intel.com Link: https://lkml.kernel.org/r/1517522386-18410-3-git-send-email-karahmed@amazon.de
2018-02-02 05:59:43 +08:00
entry->edx = 0;
/*
* IBRS, IBPB and VIRT_SSBD aren't necessarily present in
* hardware cpuid
*/
if (boot_cpu_has(X86_FEATURE_AMD_IBPB))
entry->ebx |= F(AMD_IBPB);
if (boot_cpu_has(X86_FEATURE_AMD_IBRS))
entry->ebx |= F(AMD_IBRS);
if (boot_cpu_has(X86_FEATURE_VIRT_SSBD))
entry->ebx |= F(VIRT_SSBD);
KVM/x86: Add IBPB support The Indirect Branch Predictor Barrier (IBPB) is an indirect branch control mechanism. It keeps earlier branches from influencing later ones. Unlike IBRS and STIBP, IBPB does not define a new mode of operation. It's a command that ensures predicted branch targets aren't used after the barrier. Although IBRS and IBPB are enumerated by the same CPUID enumeration, IBPB is very different. IBPB helps mitigate against three potential attacks: * Mitigate guests from being attacked by other guests. - This is addressed by issing IBPB when we do a guest switch. * Mitigate attacks from guest/ring3->host/ring3. These would require a IBPB during context switch in host, or after VMEXIT. The host process has two ways to mitigate - Either it can be compiled with retpoline - If its going through context switch, and has set !dumpable then there is a IBPB in that path. (Tim's patch: https://patchwork.kernel.org/patch/10192871) - The case where after a VMEXIT you return back to Qemu might make Qemu attackable from guest when Qemu isn't compiled with retpoline. There are issues reported when doing IBPB on every VMEXIT that resulted in some tsc calibration woes in guest. * Mitigate guest/ring0->host/ring0 attacks. When host kernel is using retpoline it is safe against these attacks. If host kernel isn't using retpoline we might need to do a IBPB flush on every VMEXIT. Even when using retpoline for indirect calls, in certain conditions 'ret' can use the BTB on Skylake-era CPUs. There are other mitigations available like RSB stuffing/clearing. * IBPB is issued only for SVM during svm_free_vcpu(). VMX has a vmclear and SVM doesn't. Follow discussion here: https://lkml.org/lkml/2018/1/15/146 Please refer to the following spec for more details on the enumeration and control. Refer here to get documentation about mitigations. https://software.intel.com/en-us/side-channel-security-support [peterz: rebase and changelog rewrite] [karahmed: - rebase - vmx: expose PRED_CMD if guest has it in CPUID - svm: only pass through IBPB if guest has it in CPUID - vmx: support !cpu_has_vmx_msr_bitmap()] - vmx: support nested] [dwmw2: Expose CPUID bit too (AMD IBPB only for now as we lack IBRS) PRED_CMD is a write-only MSR] Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: kvm@vger.kernel.org Cc: Asit Mallick <asit.k.mallick@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Jun Nakajima <jun.nakajima@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/1515720739-43819-6-git-send-email-ashok.raj@intel.com Link: https://lkml.kernel.org/r/1517522386-18410-3-git-send-email-karahmed@amazon.de
2018-02-02 05:59:43 +08:00
entry->ebx &= kvm_cpuid_8000_0008_ebx_x86_features;
cpuid_mask(&entry->ebx, CPUID_8000_0008_EBX);
/*
* The preference is to use SPEC CTRL MSR instead of the
* VIRT_SPEC MSR.
*/
if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) &&
!boot_cpu_has(X86_FEATURE_AMD_SSBD))
entry->ebx |= F(VIRT_SSBD);
break;
}
case 0x80000019:
entry->ecx = entry->edx = 0;
break;
case 0x8000001a:
break;
case 0x8000001d:
break;
/*Add support for Centaur's CPUID instruction*/
case 0xC0000000:
/*Just support up to 0xC0000004 now*/
entry->eax = min(entry->eax, 0xC0000004);
break;
case 0xC0000001:
entry->edx &= kvm_cpuid_C000_0001_edx_x86_features;
cpuid_mask(&entry->edx, CPUID_C000_0001_EDX);
break;
case 3: /* Processor serial number */
case 5: /* MONITOR/MWAIT */
case 0xC0000002:
case 0xC0000003:
case 0xC0000004:
default:
entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
break;
}
kvm_x86_ops->set_supported_cpuid(function, entry);
r = 0;
out:
put_cpu();
return r;
}
static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 func,
u32 idx, int *nent, int maxnent, unsigned int type)
{
if (type == KVM_GET_EMULATED_CPUID)
return __do_cpuid_ent_emulated(entry, func, idx, nent, maxnent);
return __do_cpuid_ent(entry, func, idx, nent, maxnent);
}
#undef F
struct kvm_cpuid_param {
u32 func;
u32 idx;
bool has_leaf_count;
bool (*qualifier)(const struct kvm_cpuid_param *param);
};
static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
{
return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
}
static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
__u32 num_entries, unsigned int ioctl_type)
{
int i;
__u32 pad[3];
if (ioctl_type != KVM_GET_EMULATED_CPUID)
return false;
/*
* We want to make sure that ->padding is being passed clean from
* userspace in case we want to use it for something in the future.
*
* Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
* have to give ourselves satisfied only with the emulated side. /me
* sheds a tear.
*/
for (i = 0; i < num_entries; i++) {
if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
return true;
if (pad[0] || pad[1] || pad[2])
return true;
}
return false;
}
int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
struct kvm_cpuid_entry2 __user *entries,
unsigned int type)
{
struct kvm_cpuid_entry2 *cpuid_entries;
int limit, nent = 0, r = -E2BIG, i;
u32 func;
static const struct kvm_cpuid_param param[] = {
{ .func = 0, .has_leaf_count = true },
{ .func = 0x80000000, .has_leaf_count = true },
{ .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
{ .func = KVM_CPUID_SIGNATURE },
{ .func = KVM_CPUID_FEATURES },
};
if (cpuid->nent < 1)
goto out;
if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
cpuid->nent = KVM_MAX_CPUID_ENTRIES;
if (sanity_check_entries(entries, cpuid->nent, type))
return -EINVAL;
r = -ENOMEM;
treewide: Use array_size() in vzalloc() The vzalloc() function has no 2-factor argument form, so multiplication factors need to be wrapped in array_size(). This patch replaces cases of: vzalloc(a * b) with: vzalloc(array_size(a, b)) as well as handling cases of: vzalloc(a * b * c) with: vzalloc(array3_size(a, b, c)) This does, however, attempt to ignore constant size factors like: vzalloc(4 * 1024) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( vzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | vzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( vzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(u8) * COUNT + COUNT , ...) | vzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | vzalloc( - sizeof(char) * COUNT + COUNT , ...) | vzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( vzalloc( - sizeof(TYPE) * (COUNT_ID) + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT_ID + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT_CONST + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vzalloc( - sizeof(THING) * (COUNT_ID) + array_size(COUNT_ID, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT_ID + array_size(COUNT_ID, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT_CONST + array_size(COUNT_CONST, sizeof(THING)) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ vzalloc( - SIZE * COUNT + array_size(COUNT, SIZE) , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( vzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( vzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | vzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( vzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( vzalloc(C1 * C2 * C3, ...) | vzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants. @@ expression E1, E2; constant C1, C2; @@ ( vzalloc(C1 * C2, ...) | vzalloc( - E1 * E2 + array_size(E1, E2) , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-13 05:27:37 +08:00
cpuid_entries = vzalloc(array_size(sizeof(struct kvm_cpuid_entry2),
cpuid->nent));
if (!cpuid_entries)
goto out;
r = 0;
for (i = 0; i < ARRAY_SIZE(param); i++) {
const struct kvm_cpuid_param *ent = &param[i];
if (ent->qualifier && !ent->qualifier(ent))
continue;
r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
&nent, cpuid->nent, type);
if (r)
goto out_free;
if (!ent->has_leaf_count)
continue;
limit = cpuid_entries[nent - 1].eax;
for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
&nent, cpuid->nent, type);
if (r)
goto out_free;
}
r = -EFAULT;
if (copy_to_user(entries, cpuid_entries,
nent * sizeof(struct kvm_cpuid_entry2)))
goto out_free;
cpuid->nent = nent;
r = 0;
out_free:
vfree(cpuid_entries);
out:
return r;
}
static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
{
struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
struct kvm_cpuid_entry2 *ej;
int j = i;
int nent = vcpu->arch.cpuid_nent;
e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
/* when no next entry is found, the current entry[i] is reselected */
do {
j = (j + 1) % nent;
ej = &vcpu->arch.cpuid_entries[j];
} while (ej->function != e->function);
ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
return j;
}
/* find an entry with matching function, matching index (if needed), and that
* should be read next (if it's stateful) */
static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
u32 function, u32 index)
{
if (e->function != function)
return 0;
if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
return 0;
if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
!(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
return 0;
return 1;
}
struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
u32 function, u32 index)
{
int i;
struct kvm_cpuid_entry2 *best = NULL;
for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
struct kvm_cpuid_entry2 *e;
e = &vcpu->arch.cpuid_entries[i];
if (is_matching_cpuid_entry(e, function, index)) {
if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
move_to_next_stateful_cpuid_entry(vcpu, i);
best = e;
break;
}
}
return best;
}
EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
/*
* If no match is found, check whether we exceed the vCPU's limit
* and return the content of the highest valid _standard_ leaf instead.
* This is to satisfy the CPUID specification.
*/
static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
u32 function, u32 index)
{
struct kvm_cpuid_entry2 *maxlevel;
maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
if (!maxlevel || maxlevel->eax >= function)
return NULL;
if (function & 0x80000000) {
maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
if (!maxlevel)
return NULL;
}
return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
}
bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
u32 *ecx, u32 *edx, bool check_limit)
{
u32 function = *eax, index = *ecx;
struct kvm_cpuid_entry2 *best;
bool entry_found = true;
best = kvm_find_cpuid_entry(vcpu, function, index);
if (!best) {
entry_found = false;
if (!check_limit)
goto out;
best = check_cpuid_limit(vcpu, function, index);
}
out:
if (best) {
*eax = best->eax;
*ebx = best->ebx;
*ecx = best->ecx;
*edx = best->edx;
} else
*eax = *ebx = *ecx = *edx = 0;
trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx, entry_found);
return entry_found;
}
EXPORT_SYMBOL_GPL(kvm_cpuid);
int kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
{
u32 eax, ebx, ecx, edx;
if (cpuid_fault_enabled(vcpu) && !kvm_require_cpl(vcpu, 0))
return 1;
eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx, true);
kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
return kvm_skip_emulated_instruction(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);