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linux/arch/s390/kvm/vsie.c
Janis Schoetterl-Glausch 7119decf47 KVM: s390: Enable specification exception interpretation 
When this feature is enabled the hardware is free to interpret
specification exceptions generated by the guest, instead of causing
program interruption interceptions.

This benefits (test) programs that generate a lot of specification
exceptions (roughly 4x increase in exceptions/sec).

Interceptions will occur as before if ICTL_PINT is set,
i.e. if guest debug is enabled.

There is no indication if this feature is available or not and the
hardware is free to interpret or not. So we can simply set this bit and
if the hardware ignores it we fall back to intercept 8 handling.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Link: https://lore.kernel.org/linux-s390/20210706114714.3936825-1-scgl@linux.ibm.com/
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2021-08-27 18:35:20 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* kvm nested virtualization support for s390x
*
* Copyright IBM Corp. 2016, 2018
*
* Author(s): David Hildenbrand <dahi@linux.vnet.ibm.com>
*/
#include <linux/vmalloc.h>
#include <linux/kvm_host.h>
#include <linux/bug.h>
#include <linux/list.h>
#include <linux/bitmap.h>
#include <linux/sched/signal.h>
#include <asm/gmap.h>
#include <asm/mmu_context.h>
#include <asm/sclp.h>
#include <asm/nmi.h>
#include <asm/dis.h>
#include <asm/fpu/api.h>
#include "kvm-s390.h"
#include "gaccess.h"
struct vsie_page {
struct kvm_s390_sie_block scb_s; /* 0x0000 */
/*
* the backup info for machine check. ensure it's at
* the same offset as that in struct sie_page!
*/
struct mcck_volatile_info mcck_info; /* 0x0200 */
/*
* The pinned original scb. Be aware that other VCPUs can modify
* it while we read from it. Values that are used for conditions or
* are reused conditionally, should be accessed via READ_ONCE.
*/
struct kvm_s390_sie_block *scb_o; /* 0x0218 */
/* the shadow gmap in use by the vsie_page */
struct gmap *gmap; /* 0x0220 */
/* address of the last reported fault to guest2 */
unsigned long fault_addr; /* 0x0228 */
/* calculated guest addresses of satellite control blocks */
gpa_t sca_gpa; /* 0x0230 */
gpa_t itdba_gpa; /* 0x0238 */
gpa_t gvrd_gpa; /* 0x0240 */
gpa_t riccbd_gpa; /* 0x0248 */
gpa_t sdnx_gpa; /* 0x0250 */
__u8 reserved[0x0700 - 0x0258]; /* 0x0258 */
struct kvm_s390_crypto_cb crycb; /* 0x0700 */
__u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE]; /* 0x0800 */
};
/* trigger a validity icpt for the given scb */
static int set_validity_icpt(struct kvm_s390_sie_block *scb,
__u16 reason_code)
{
scb->ipa = 0x1000;
scb->ipb = ((__u32) reason_code) << 16;
scb->icptcode = ICPT_VALIDITY;
return 1;
}
/* mark the prefix as unmapped, this will block the VSIE */
static void prefix_unmapped(struct vsie_page *vsie_page)
{
atomic_or(PROG_REQUEST, &vsie_page->scb_s.prog20);
}
/* mark the prefix as unmapped and wait until the VSIE has been left */
static void prefix_unmapped_sync(struct vsie_page *vsie_page)
{
prefix_unmapped(vsie_page);
if (vsie_page->scb_s.prog0c & PROG_IN_SIE)
atomic_or(CPUSTAT_STOP_INT, &vsie_page->scb_s.cpuflags);
while (vsie_page->scb_s.prog0c & PROG_IN_SIE)
cpu_relax();
}
/* mark the prefix as mapped, this will allow the VSIE to run */
static void prefix_mapped(struct vsie_page *vsie_page)
{
atomic_andnot(PROG_REQUEST, &vsie_page->scb_s.prog20);
}
/* test if the prefix is mapped into the gmap shadow */
static int prefix_is_mapped(struct vsie_page *vsie_page)
{
return !(atomic_read(&vsie_page->scb_s.prog20) & PROG_REQUEST);
}
/* copy the updated intervention request bits into the shadow scb */
static void update_intervention_requests(struct vsie_page *vsie_page)
{
const int bits = CPUSTAT_STOP_INT | CPUSTAT_IO_INT | CPUSTAT_EXT_INT;
int cpuflags;
cpuflags = atomic_read(&vsie_page->scb_o->cpuflags);
atomic_andnot(bits, &vsie_page->scb_s.cpuflags);
atomic_or(cpuflags & bits, &vsie_page->scb_s.cpuflags);
}
/* shadow (filter and validate) the cpuflags */
static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
int newflags, cpuflags = atomic_read(&scb_o->cpuflags);
/* we don't allow ESA/390 guests */
if (!(cpuflags & CPUSTAT_ZARCH))
return set_validity_icpt(scb_s, 0x0001U);
if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS))
return set_validity_icpt(scb_s, 0x0001U);
else if (cpuflags & (CPUSTAT_SLSV | CPUSTAT_SLSR))
return set_validity_icpt(scb_s, 0x0007U);
/* intervention requests will be set later */
newflags = CPUSTAT_ZARCH;
if (cpuflags & CPUSTAT_GED && test_kvm_facility(vcpu->kvm, 8))
newflags |= CPUSTAT_GED;
if (cpuflags & CPUSTAT_GED2 && test_kvm_facility(vcpu->kvm, 78)) {
if (cpuflags & CPUSTAT_GED)
return set_validity_icpt(scb_s, 0x0001U);
newflags |= CPUSTAT_GED2;
}
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GPERE))
newflags |= cpuflags & CPUSTAT_P;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GSLS))
newflags |= cpuflags & CPUSTAT_SM;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IBS))
newflags |= cpuflags & CPUSTAT_IBS;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_KSS))
newflags |= cpuflags & CPUSTAT_KSS;
atomic_set(&scb_s->cpuflags, newflags);
return 0;
}
/* Copy to APCB FORMAT1 from APCB FORMAT0 */
static int setup_apcb10(struct kvm_vcpu *vcpu, struct kvm_s390_apcb1 *apcb_s,
unsigned long apcb_o, struct kvm_s390_apcb1 *apcb_h)
{
struct kvm_s390_apcb0 tmp;
if (read_guest_real(vcpu, apcb_o, &tmp, sizeof(struct kvm_s390_apcb0)))
return -EFAULT;
apcb_s->apm[0] = apcb_h->apm[0] & tmp.apm[0];
apcb_s->aqm[0] = apcb_h->aqm[0] & tmp.aqm[0] & 0xffff000000000000UL;
apcb_s->adm[0] = apcb_h->adm[0] & tmp.adm[0] & 0xffff000000000000UL;
return 0;
}
/**
* setup_apcb00 - Copy to APCB FORMAT0 from APCB FORMAT0
* @vcpu: pointer to the virtual CPU
* @apcb_s: pointer to start of apcb in the shadow crycb
* @apcb_o: pointer to start of original apcb in the guest2
* @apcb_h: pointer to start of apcb in the guest1
*
* Returns 0 and -EFAULT on error reading guest apcb
*/
static int setup_apcb00(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
unsigned long apcb_o, unsigned long *apcb_h)
{
if (read_guest_real(vcpu, apcb_o, apcb_s,
sizeof(struct kvm_s390_apcb0)))
return -EFAULT;
bitmap_and(apcb_s, apcb_s, apcb_h, sizeof(struct kvm_s390_apcb0));
return 0;
}
/**
* setup_apcb11 - Copy the FORMAT1 APCB from the guest to the shadow CRYCB
* @vcpu: pointer to the virtual CPU
* @apcb_s: pointer to start of apcb in the shadow crycb
* @apcb_o: pointer to start of original guest apcb
* @apcb_h: pointer to start of apcb in the host
*
* Returns 0 and -EFAULT on error reading guest apcb
*/
static int setup_apcb11(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
unsigned long apcb_o,
unsigned long *apcb_h)
{
if (read_guest_real(vcpu, apcb_o, apcb_s,
sizeof(struct kvm_s390_apcb1)))
return -EFAULT;
bitmap_and(apcb_s, apcb_s, apcb_h, sizeof(struct kvm_s390_apcb1));
return 0;
}
/**
* setup_apcb - Create a shadow copy of the apcb.
* @vcpu: pointer to the virtual CPU
* @crycb_s: pointer to shadow crycb
* @crycb_o: pointer to original guest crycb
* @crycb_h: pointer to the host crycb
* @fmt_o: format of the original guest crycb.
* @fmt_h: format of the host crycb.
*
* Checks the compatibility between the guest and host crycb and calls the
* appropriate copy function.
*
* Return 0 or an error number if the guest and host crycb are incompatible.
*/
static int setup_apcb(struct kvm_vcpu *vcpu, struct kvm_s390_crypto_cb *crycb_s,
const u32 crycb_o,
struct kvm_s390_crypto_cb *crycb_h,
int fmt_o, int fmt_h)
{
struct kvm_s390_crypto_cb *crycb;
crycb = (struct kvm_s390_crypto_cb *) (unsigned long)crycb_o;
switch (fmt_o) {
case CRYCB_FORMAT2:
if ((crycb_o & PAGE_MASK) != ((crycb_o + 256) & PAGE_MASK))
return -EACCES;
if (fmt_h != CRYCB_FORMAT2)
return -EINVAL;
return setup_apcb11(vcpu, (unsigned long *)&crycb_s->apcb1,
(unsigned long) &crycb->apcb1,
(unsigned long *)&crycb_h->apcb1);
case CRYCB_FORMAT1:
switch (fmt_h) {
case CRYCB_FORMAT2:
return setup_apcb10(vcpu, &crycb_s->apcb1,
(unsigned long) &crycb->apcb0,
&crycb_h->apcb1);
case CRYCB_FORMAT1:
return setup_apcb00(vcpu,
(unsigned long *) &crycb_s->apcb0,
(unsigned long) &crycb->apcb0,
(unsigned long *) &crycb_h->apcb0);
}
break;
case CRYCB_FORMAT0:
if ((crycb_o & PAGE_MASK) != ((crycb_o + 32) & PAGE_MASK))
return -EACCES;
switch (fmt_h) {
case CRYCB_FORMAT2:
return setup_apcb10(vcpu, &crycb_s->apcb1,
(unsigned long) &crycb->apcb0,
&crycb_h->apcb1);
case CRYCB_FORMAT1:
case CRYCB_FORMAT0:
return setup_apcb00(vcpu,
(unsigned long *) &crycb_s->apcb0,
(unsigned long) &crycb->apcb0,
(unsigned long *) &crycb_h->apcb0);
}
}
return -EINVAL;
}
/**
* shadow_crycb - Create a shadow copy of the crycb block
* @vcpu: a pointer to the virtual CPU
* @vsie_page: a pointer to internal date used for the vSIE
*
* Create a shadow copy of the crycb block and setup key wrapping, if
* requested for guest 3 and enabled for guest 2.
*
* We accept format-1 or format-2, but we convert format-1 into format-2
* in the shadow CRYCB.
* Using format-2 enables the firmware to choose the right format when
* scheduling the SIE.
* There is nothing to do for format-0.
*
* This function centralize the issuing of set_validity_icpt() for all
* the subfunctions working on the crycb.
*
* Returns: - 0 if shadowed or nothing to do
* - > 0 if control has to be given to guest 2
*/
static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
const uint32_t crycbd_o = READ_ONCE(scb_o->crycbd);
const u32 crycb_addr = crycbd_o & 0x7ffffff8U;
unsigned long *b1, *b2;
u8 ecb3_flags;
u32 ecd_flags;
int apie_h;
int apie_s;
int key_msk = test_kvm_facility(vcpu->kvm, 76);
int fmt_o = crycbd_o & CRYCB_FORMAT_MASK;
int fmt_h = vcpu->arch.sie_block->crycbd & CRYCB_FORMAT_MASK;
int ret = 0;
scb_s->crycbd = 0;
apie_h = vcpu->arch.sie_block->eca & ECA_APIE;
apie_s = apie_h & scb_o->eca;
if (!apie_s && (!key_msk || (fmt_o == CRYCB_FORMAT0)))
return 0;
if (!crycb_addr)
return set_validity_icpt(scb_s, 0x0039U);
if (fmt_o == CRYCB_FORMAT1)
if ((crycb_addr & PAGE_MASK) !=
((crycb_addr + 128) & PAGE_MASK))
return set_validity_icpt(scb_s, 0x003CU);
if (apie_s) {
ret = setup_apcb(vcpu, &vsie_page->crycb, crycb_addr,
vcpu->kvm->arch.crypto.crycb,
fmt_o, fmt_h);
if (ret)
goto end;
scb_s->eca |= scb_o->eca & ECA_APIE;
}
/* we may only allow it if enabled for guest 2 */
ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 &
(ECB3_AES | ECB3_DEA);
ecd_flags = scb_o->ecd & vcpu->arch.sie_block->ecd & ECD_ECC;
if (!ecb3_flags && !ecd_flags)
goto end;
/* copy only the wrapping keys */
if (read_guest_real(vcpu, crycb_addr + 72,
vsie_page->crycb.dea_wrapping_key_mask, 56))
return set_validity_icpt(scb_s, 0x0035U);
scb_s->ecb3 |= ecb3_flags;
scb_s->ecd |= ecd_flags;
/* xor both blocks in one run */
b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask;
b2 = (unsigned long *)
vcpu->kvm->arch.crypto.crycb->dea_wrapping_key_mask;
/* as 56%8 == 0, bitmap_xor won't overwrite any data */
bitmap_xor(b1, b1, b2, BITS_PER_BYTE * 56);
end:
switch (ret) {
case -EINVAL:
return set_validity_icpt(scb_s, 0x0022U);
case -EFAULT:
return set_validity_icpt(scb_s, 0x0035U);
case -EACCES:
return set_validity_icpt(scb_s, 0x003CU);
}
scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT2;
return 0;
}
/* shadow (round up/down) the ibc to avoid validity icpt */
static void prepare_ibc(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
/* READ_ONCE does not work on bitfields - use a temporary variable */
const uint32_t __new_ibc = scb_o->ibc;
const uint32_t new_ibc = READ_ONCE(__new_ibc) & 0x0fffU;
__u64 min_ibc = (sclp.ibc >> 16) & 0x0fffU;
scb_s->ibc = 0;
/* ibc installed in g2 and requested for g3 */
if (vcpu->kvm->arch.model.ibc && new_ibc) {
scb_s->ibc = new_ibc;
/* takte care of the minimum ibc level of the machine */
if (scb_s->ibc < min_ibc)
scb_s->ibc = min_ibc;
/* take care of the maximum ibc level set for the guest */
if (scb_s->ibc > vcpu->kvm->arch.model.ibc)
scb_s->ibc = vcpu->kvm->arch.model.ibc;
}
}
/* unshadow the scb, copying parameters back to the real scb */
static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
/* interception */
scb_o->icptcode = scb_s->icptcode;
scb_o->icptstatus = scb_s->icptstatus;
scb_o->ipa = scb_s->ipa;
scb_o->ipb = scb_s->ipb;
scb_o->gbea = scb_s->gbea;
/* timer */
scb_o->cputm = scb_s->cputm;
scb_o->ckc = scb_s->ckc;
scb_o->todpr = scb_s->todpr;
/* guest state */
scb_o->gpsw = scb_s->gpsw;
scb_o->gg14 = scb_s->gg14;
scb_o->gg15 = scb_s->gg15;
memcpy(scb_o->gcr, scb_s->gcr, 128);
scb_o->pp = scb_s->pp;
/* branch prediction */
if (test_kvm_facility(vcpu->kvm, 82)) {
scb_o->fpf &= ~FPF_BPBC;
scb_o->fpf |= scb_s->fpf & FPF_BPBC;
}
/* interrupt intercept */
switch (scb_s->icptcode) {
case ICPT_PROGI:
case ICPT_INSTPROGI:
case ICPT_EXTINT:
memcpy((void *)((u64)scb_o + 0xc0),
(void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0);
break;
}
if (scb_s->ihcpu != 0xffffU)
scb_o->ihcpu = scb_s->ihcpu;
}
/*
* Setup the shadow scb by copying and checking the relevant parts of the g2
* provided scb.
*
* Returns: - 0 if the scb has been shadowed
* - > 0 if control has to be given to guest 2
*/
static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
/* READ_ONCE does not work on bitfields - use a temporary variable */
const uint32_t __new_prefix = scb_o->prefix;
const uint32_t new_prefix = READ_ONCE(__new_prefix);
const bool wants_tx = READ_ONCE(scb_o->ecb) & ECB_TE;
bool had_tx = scb_s->ecb & ECB_TE;
unsigned long new_mso = 0;
int rc;
/* make sure we don't have any leftovers when reusing the scb */
scb_s->icptcode = 0;
scb_s->eca = 0;
scb_s->ecb = 0;
scb_s->ecb2 = 0;
scb_s->ecb3 = 0;
scb_s->ecd = 0;
scb_s->fac = 0;
scb_s->fpf = 0;
rc = prepare_cpuflags(vcpu, vsie_page);
if (rc)
goto out;
/* timer */
scb_s->cputm = scb_o->cputm;
scb_s->ckc = scb_o->ckc;
scb_s->todpr = scb_o->todpr;
scb_s->epoch = scb_o->epoch;
/* guest state */
scb_s->gpsw = scb_o->gpsw;
scb_s->gg14 = scb_o->gg14;
scb_s->gg15 = scb_o->gg15;
memcpy(scb_s->gcr, scb_o->gcr, 128);
scb_s->pp = scb_o->pp;
/* interception / execution handling */
scb_s->gbea = scb_o->gbea;
scb_s->lctl = scb_o->lctl;
scb_s->svcc = scb_o->svcc;
scb_s->ictl = scb_o->ictl;
/*
* SKEY handling functions can't deal with false setting of PTE invalid
* bits. Therefore we cannot provide interpretation and would later
* have to provide own emulation handlers.
*/
if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_KSS))
scb_s->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE;
scb_s->icpua = scb_o->icpua;
if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_SM))
new_mso = READ_ONCE(scb_o->mso) & 0xfffffffffff00000UL;
/* if the hva of the prefix changes, we have to remap the prefix */
if (scb_s->mso != new_mso || scb_s->prefix != new_prefix)
prefix_unmapped(vsie_page);
/* SIE will do mso/msl validity and exception checks for us */
scb_s->msl = scb_o->msl & 0xfffffffffff00000UL;
scb_s->mso = new_mso;
scb_s->prefix = new_prefix;
/* We have to definetly flush the tlb if this scb never ran */
if (scb_s->ihcpu != 0xffffU)
scb_s->ihcpu = scb_o->ihcpu;
/* MVPG and Protection Exception Interpretation are always available */
scb_s->eca |= scb_o->eca & (ECA_MVPGI | ECA_PROTEXCI);
/* Host-protection-interruption introduced with ESOP */
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_ESOP))
scb_s->ecb |= scb_o->ecb & ECB_HOSTPROTINT;
/* transactional execution */
if (test_kvm_facility(vcpu->kvm, 73) && wants_tx) {
/* remap the prefix is tx is toggled on */
if (!had_tx)
prefix_unmapped(vsie_page);
scb_s->ecb |= ECB_TE;
}
/* specification exception interpretation */
scb_s->ecb |= scb_o->ecb & ECB_SPECI;
/* branch prediction */
if (test_kvm_facility(vcpu->kvm, 82))
scb_s->fpf |= scb_o->fpf & FPF_BPBC;
/* SIMD */
if (test_kvm_facility(vcpu->kvm, 129)) {
scb_s->eca |= scb_o->eca & ECA_VX;
scb_s->ecd |= scb_o->ecd & ECD_HOSTREGMGMT;
}
/* Run-time-Instrumentation */
if (test_kvm_facility(vcpu->kvm, 64))
scb_s->ecb3 |= scb_o->ecb3 & ECB3_RI;
/* Instruction Execution Prevention */
if (test_kvm_facility(vcpu->kvm, 130))
scb_s->ecb2 |= scb_o->ecb2 & ECB2_IEP;
/* Guarded Storage */
if (test_kvm_facility(vcpu->kvm, 133)) {
scb_s->ecb |= scb_o->ecb & ECB_GS;
scb_s->ecd |= scb_o->ecd & ECD_HOSTREGMGMT;
}
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIIF))
scb_s->eca |= scb_o->eca & ECA_SII;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IB))
scb_s->eca |= scb_o->eca & ECA_IB;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI))
scb_s->eca |= scb_o->eca & ECA_CEI;
/* Epoch Extension */
if (test_kvm_facility(vcpu->kvm, 139))
scb_s->ecd |= scb_o->ecd & ECD_MEF;
/* etoken */
if (test_kvm_facility(vcpu->kvm, 156))
scb_s->ecd |= scb_o->ecd & ECD_ETOKENF;
scb_s->hpid = HPID_VSIE;
scb_s->cpnc = scb_o->cpnc;
prepare_ibc(vcpu, vsie_page);
rc = shadow_crycb(vcpu, vsie_page);
out:
if (rc)
unshadow_scb(vcpu, vsie_page);
return rc;
}
void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
unsigned long end)
{
struct kvm *kvm = gmap->private;
struct vsie_page *cur;
unsigned long prefix;
struct page *page;
int i;
if (!gmap_is_shadow(gmap))
return;
if (start >= 1UL << 31)
/* We are only interested in prefix pages */
return;
/*
* Only new shadow blocks are added to the list during runtime,
* therefore we can safely reference them all the time.
*/
for (i = 0; i < kvm->arch.vsie.page_count; i++) {
page = READ_ONCE(kvm->arch.vsie.pages[i]);
if (!page)
continue;
cur = page_to_virt(page);
if (READ_ONCE(cur->gmap) != gmap)
continue;
prefix = cur->scb_s.prefix << GUEST_PREFIX_SHIFT;
/* with mso/msl, the prefix lies at an offset */
prefix += cur->scb_s.mso;
if (prefix <= end && start <= prefix + 2 * PAGE_SIZE - 1)
prefix_unmapped_sync(cur);
}
}
/*
* Map the first prefix page and if tx is enabled also the second prefix page.
*
* The prefix will be protected, a gmap notifier will inform about unmaps.
* The shadow scb must not be executed until the prefix is remapped, this is
* guaranteed by properly handling PROG_REQUEST.
*
* Returns: - 0 on if successfully mapped or already mapped
* - > 0 if control has to be given to guest 2
* - -EAGAIN if the caller can retry immediately
* - -ENOMEM if out of memory
*/
static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
u64 prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
int rc;
if (prefix_is_mapped(vsie_page))
return 0;
/* mark it as mapped so we can catch any concurrent unmappers */
prefix_mapped(vsie_page);
/* with mso/msl, the prefix lies at offset *mso* */
prefix += scb_s->mso;
rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix, NULL);
if (!rc && (scb_s->ecb & ECB_TE))
rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
prefix + PAGE_SIZE, NULL);
/*
* We don't have to mprotect, we will be called for all unshadows.
* SIE will detect if protection applies and trigger a validity.
*/
if (rc)
prefix_unmapped(vsie_page);
if (rc > 0 || rc == -EFAULT)
rc = set_validity_icpt(scb_s, 0x0037U);
return rc;
}
/*
* Pin the guest page given by gpa and set hpa to the pinned host address.
* Will always be pinned writable.
*
* Returns: - 0 on success
* - -EINVAL if the gpa is not valid guest storage
*/
static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa)
{
struct page *page;
page = gfn_to_page(kvm, gpa_to_gfn(gpa));
if (is_error_page(page))
return -EINVAL;
*hpa = (hpa_t) page_to_virt(page) + (gpa & ~PAGE_MASK);
return 0;
}
/* Unpins a page previously pinned via pin_guest_page, marking it as dirty. */
static void unpin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t hpa)
{
kvm_release_pfn_dirty(hpa >> PAGE_SHIFT);
/* mark the page always as dirty for migration */
mark_page_dirty(kvm, gpa_to_gfn(gpa));
}
/* unpin all blocks previously pinned by pin_blocks(), marking them dirty */
static void unpin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
hpa_t hpa;
hpa = (u64) scb_s->scaoh << 32 | scb_s->scaol;
if (hpa) {
unpin_guest_page(vcpu->kvm, vsie_page->sca_gpa, hpa);
vsie_page->sca_gpa = 0;
scb_s->scaol = 0;
scb_s->scaoh = 0;
}
hpa = scb_s->itdba;
if (hpa) {
unpin_guest_page(vcpu->kvm, vsie_page->itdba_gpa, hpa);
vsie_page->itdba_gpa = 0;
scb_s->itdba = 0;
}
hpa = scb_s->gvrd;
if (hpa) {
unpin_guest_page(vcpu->kvm, vsie_page->gvrd_gpa, hpa);
vsie_page->gvrd_gpa = 0;
scb_s->gvrd = 0;
}
hpa = scb_s->riccbd;
if (hpa) {
unpin_guest_page(vcpu->kvm, vsie_page->riccbd_gpa, hpa);
vsie_page->riccbd_gpa = 0;
scb_s->riccbd = 0;
}
hpa = scb_s->sdnxo;
if (hpa) {
unpin_guest_page(vcpu->kvm, vsie_page->sdnx_gpa, hpa);
vsie_page->sdnx_gpa = 0;
scb_s->sdnxo = 0;
}
}
/*
* Instead of shadowing some blocks, we can simply forward them because the
* addresses in the scb are 64 bit long.
*
* This works as long as the data lies in one page. If blocks ever exceed one
* page, we have to fall back to shadowing.
*
* As we reuse the sca, the vcpu pointers contained in it are invalid. We must
* therefore not enable any facilities that access these pointers (e.g. SIGPIF).
*
* Returns: - 0 if all blocks were pinned.
* - > 0 if control has to be given to guest 2
* - -ENOMEM if out of memory
*/
static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
hpa_t hpa;
gpa_t gpa;
int rc = 0;
gpa = READ_ONCE(scb_o->scaol) & ~0xfUL;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO))
gpa |= (u64) READ_ONCE(scb_o->scaoh) << 32;
if (gpa) {
if (gpa < 2 * PAGE_SIZE)
rc = set_validity_icpt(scb_s, 0x0038U);
else if ((gpa & ~0x1fffUL) == kvm_s390_get_prefix(vcpu))
rc = set_validity_icpt(scb_s, 0x0011U);
else if ((gpa & PAGE_MASK) !=
((gpa + sizeof(struct bsca_block) - 1) & PAGE_MASK))
rc = set_validity_icpt(scb_s, 0x003bU);
if (!rc) {
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc)
rc = set_validity_icpt(scb_s, 0x0034U);
}
if (rc)
goto unpin;
vsie_page->sca_gpa = gpa;
scb_s->scaoh = (u32)((u64)hpa >> 32);
scb_s->scaol = (u32)(u64)hpa;
}
gpa = READ_ONCE(scb_o->itdba) & ~0xffUL;
if (gpa && (scb_s->ecb & ECB_TE)) {
if (gpa < 2 * PAGE_SIZE) {
rc = set_validity_icpt(scb_s, 0x0080U);
goto unpin;
}
/* 256 bytes cannot cross page boundaries */
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc) {
rc = set_validity_icpt(scb_s, 0x0080U);
goto unpin;
}
vsie_page->itdba_gpa = gpa;
scb_s->itdba = hpa;
}
gpa = READ_ONCE(scb_o->gvrd) & ~0x1ffUL;
if (gpa && (scb_s->eca & ECA_VX) && !(scb_s->ecd & ECD_HOSTREGMGMT)) {
if (gpa < 2 * PAGE_SIZE) {
rc = set_validity_icpt(scb_s, 0x1310U);
goto unpin;
}
/*
* 512 bytes vector registers cannot cross page boundaries
* if this block gets bigger, we have to shadow it.
*/
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc) {
rc = set_validity_icpt(scb_s, 0x1310U);
goto unpin;
}
vsie_page->gvrd_gpa = gpa;
scb_s->gvrd = hpa;
}
gpa = READ_ONCE(scb_o->riccbd) & ~0x3fUL;
if (gpa && (scb_s->ecb3 & ECB3_RI)) {
if (gpa < 2 * PAGE_SIZE) {
rc = set_validity_icpt(scb_s, 0x0043U);
goto unpin;
}
/* 64 bytes cannot cross page boundaries */
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc) {
rc = set_validity_icpt(scb_s, 0x0043U);
goto unpin;
}
/* Validity 0x0044 will be checked by SIE */
vsie_page->riccbd_gpa = gpa;
scb_s->riccbd = hpa;
}
if (((scb_s->ecb & ECB_GS) && !(scb_s->ecd & ECD_HOSTREGMGMT)) ||
(scb_s->ecd & ECD_ETOKENF)) {
unsigned long sdnxc;
gpa = READ_ONCE(scb_o->sdnxo) & ~0xfUL;
sdnxc = READ_ONCE(scb_o->sdnxo) & 0xfUL;
if (!gpa || gpa < 2 * PAGE_SIZE) {
rc = set_validity_icpt(scb_s, 0x10b0U);
goto unpin;
}
if (sdnxc < 6 || sdnxc > 12) {
rc = set_validity_icpt(scb_s, 0x10b1U);
goto unpin;
}
if (gpa & ((1 << sdnxc) - 1)) {
rc = set_validity_icpt(scb_s, 0x10b2U);
goto unpin;
}
/* Due to alignment rules (checked above) this cannot
* cross page boundaries
*/
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc) {
rc = set_validity_icpt(scb_s, 0x10b0U);
goto unpin;
}
vsie_page->sdnx_gpa = gpa;
scb_s->sdnxo = hpa | sdnxc;
}
return 0;
unpin:
unpin_blocks(vcpu, vsie_page);
return rc;
}
/* unpin the scb provided by guest 2, marking it as dirty */
static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
gpa_t gpa)
{
hpa_t hpa = (hpa_t) vsie_page->scb_o;
if (hpa)
unpin_guest_page(vcpu->kvm, gpa, hpa);
vsie_page->scb_o = NULL;
}
/*
* Pin the scb at gpa provided by guest 2 at vsie_page->scb_o.
*
* Returns: - 0 if the scb was pinned.
* - > 0 if control has to be given to guest 2
*/
static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
gpa_t gpa)
{
hpa_t hpa;
int rc;
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc) {
rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
WARN_ON_ONCE(rc);
return 1;
}
vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa;
return 0;
}
/*
* Inject a fault into guest 2.
*
* Returns: - > 0 if control has to be given to guest 2
* < 0 if an error occurred during injection.
*/
static int inject_fault(struct kvm_vcpu *vcpu, __u16 code, __u64 vaddr,
bool write_flag)
{
struct kvm_s390_pgm_info pgm = {
.code = code,
.trans_exc_code =
/* 0-51: virtual address */
(vaddr & 0xfffffffffffff000UL) |
/* 52-53: store / fetch */
(((unsigned int) !write_flag) + 1) << 10,
/* 62-63: asce id (alway primary == 0) */
.exc_access_id = 0, /* always primary */
.op_access_id = 0, /* not MVPG */
};
int rc;
if (code == PGM_PROTECTION)
pgm.trans_exc_code |= 0x4UL;
rc = kvm_s390_inject_prog_irq(vcpu, &pgm);
return rc ? rc : 1;
}
/*
* Handle a fault during vsie execution on a gmap shadow.
*
* Returns: - 0 if the fault was resolved
* - > 0 if control has to be given to guest 2
* - < 0 if an error occurred
*/
static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
int rc;
if (current->thread.gmap_int_code == PGM_PROTECTION)
/* we can directly forward all protection exceptions */
return inject_fault(vcpu, PGM_PROTECTION,
current->thread.gmap_addr, 1);
rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
current->thread.gmap_addr, NULL);
if (rc > 0) {
rc = inject_fault(vcpu, rc,
current->thread.gmap_addr,
current->thread.gmap_write_flag);
if (rc >= 0)
vsie_page->fault_addr = current->thread.gmap_addr;
}
return rc;
}
/*
* Retry the previous fault that required guest 2 intervention. This avoids
* one superfluous SIE re-entry and direct exit.
*
* Will ignore any errors. The next SIE fault will do proper fault handling.
*/
static void handle_last_fault(struct kvm_vcpu *vcpu,
struct vsie_page *vsie_page)
{
if (vsie_page->fault_addr)
kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
vsie_page->fault_addr, NULL);
vsie_page->fault_addr = 0;
}
static inline void clear_vsie_icpt(struct vsie_page *vsie_page)
{
vsie_page->scb_s.icptcode = 0;
}
/* rewind the psw and clear the vsie icpt, so we can retry execution */
static void retry_vsie_icpt(struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
int ilen = insn_length(scb_s->ipa >> 8);
/* take care of EXECUTE instructions */
if (scb_s->icptstatus & 1) {
ilen = (scb_s->icptstatus >> 4) & 0x6;
if (!ilen)
ilen = 4;
}
scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, ilen);
clear_vsie_icpt(vsie_page);
}
/*
* Try to shadow + enable the guest 2 provided facility list.
* Retry instruction execution if enabled for and provided by guest 2.
*
* Returns: - 0 if handled (retry or guest 2 icpt)
* - > 0 if control has to be given to guest 2
*/
static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
__u32 fac = READ_ONCE(vsie_page->scb_o->fac) & 0x7ffffff8U;
if (fac && test_kvm_facility(vcpu->kvm, 7)) {
retry_vsie_icpt(vsie_page);
if (read_guest_real(vcpu, fac, &vsie_page->fac,
sizeof(vsie_page->fac)))
return set_validity_icpt(scb_s, 0x1090U);
scb_s->fac = (__u32)(__u64) &vsie_page->fac;
}
return 0;
}
/*
* Get a register for a nested guest.
* @vcpu the vcpu of the guest
* @vsie_page the vsie_page for the nested guest
* @reg the register number, the upper 4 bits are ignored.
* returns: the value of the register.
*/
static u64 vsie_get_register(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, u8 reg)
{
/* no need to validate the parameter and/or perform error handling */
reg &= 0xf;
switch (reg) {
case 15:
return vsie_page->scb_s.gg15;
case 14:
return vsie_page->scb_s.gg14;
default:
return vcpu->run->s.regs.gprs[reg];
}
}
static int vsie_handle_mvpg(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
unsigned long pei_dest, pei_src, src, dest, mask, prefix;
u64 *pei_block = &vsie_page->scb_o->mcic;
int edat, rc_dest, rc_src;
union ctlreg0 cr0;
cr0.val = vcpu->arch.sie_block->gcr[0];
edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
mask = _kvm_s390_logical_to_effective(&scb_s->gpsw, PAGE_MASK);
prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
dest = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20) & mask;
dest = _kvm_s390_real_to_abs(prefix, dest) + scb_s->mso;
src = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16) & mask;
src = _kvm_s390_real_to_abs(prefix, src) + scb_s->mso;
rc_dest = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, dest, &pei_dest);
rc_src = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, src, &pei_src);
/*
* Either everything went well, or something non-critical went wrong
* e.g. because of a race. In either case, simply retry.
*/
if (rc_dest == -EAGAIN || rc_src == -EAGAIN || (!rc_dest && !rc_src)) {
retry_vsie_icpt(vsie_page);
return -EAGAIN;
}
/* Something more serious went wrong, propagate the error */
if (rc_dest < 0)
return rc_dest;
if (rc_src < 0)
return rc_src;
/* The only possible suppressing exception: just deliver it */
if (rc_dest == PGM_TRANSLATION_SPEC || rc_src == PGM_TRANSLATION_SPEC) {
clear_vsie_icpt(vsie_page);
rc_dest = kvm_s390_inject_program_int(vcpu, PGM_TRANSLATION_SPEC);
WARN_ON_ONCE(rc_dest);
return 1;
}
/*
* Forward the PEI intercept to the guest if it was a page fault, or
* also for segment and region table faults if EDAT applies.
*/
if (edat) {
rc_dest = rc_dest == PGM_ASCE_TYPE ? rc_dest : 0;
rc_src = rc_src == PGM_ASCE_TYPE ? rc_src : 0;
} else {
rc_dest = rc_dest != PGM_PAGE_TRANSLATION ? rc_dest : 0;
rc_src = rc_src != PGM_PAGE_TRANSLATION ? rc_src : 0;
}
if (!rc_dest && !rc_src) {
pei_block[0] = pei_dest;
pei_block[1] = pei_src;
return 1;
}
retry_vsie_icpt(vsie_page);
/*
* The host has edat, and the guest does not, or it was an ASCE type
* exception. The host needs to inject the appropriate DAT interrupts
* into the guest.
*/
if (rc_dest)
return inject_fault(vcpu, rc_dest, dest, 1);
return inject_fault(vcpu, rc_src, src, 0);
}
/*
* Run the vsie on a shadow scb and a shadow gmap, without any further
* sanity checks, handling SIE faults.
*
* Returns: - 0 everything went fine
* - > 0 if control has to be given to guest 2
* - < 0 if an error occurred
*/
static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
__releases(vcpu->kvm->srcu)
__acquires(vcpu->kvm->srcu)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
int guest_bp_isolation;
int rc = 0;
handle_last_fault(vcpu, vsie_page);
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
/* save current guest state of bp isolation override */
guest_bp_isolation = test_thread_flag(TIF_ISOLATE_BP_GUEST);
/*
* The guest is running with BPBC, so we have to force it on for our
* nested guest. This is done by enabling BPBC globally, so the BPBC
* control in the SCB (which the nested guest can modify) is simply
* ignored.
*/
if (test_kvm_facility(vcpu->kvm, 82) &&
vcpu->arch.sie_block->fpf & FPF_BPBC)
set_thread_flag(TIF_ISOLATE_BP_GUEST);
local_irq_disable();
guest_enter_irqoff();
local_irq_enable();
/*
* Simulate a SIE entry of the VCPU (see sie64a), so VCPU blocking
* and VCPU requests also hinder the vSIE from running and lead
* to an immediate exit. kvm_s390_vsie_kick() has to be used to
* also kick the vSIE.
*/
vcpu->arch.sie_block->prog0c |= PROG_IN_SIE;
barrier();
if (test_cpu_flag(CIF_FPU))
load_fpu_regs();
if (!kvm_s390_vcpu_sie_inhibited(vcpu))
rc = sie64a(scb_s, vcpu->run->s.regs.gprs);
barrier();
vcpu->arch.sie_block->prog0c &= ~PROG_IN_SIE;
local_irq_disable();
guest_exit_irqoff();
local_irq_enable();
/* restore guest state for bp isolation override */
if (!guest_bp_isolation)
clear_thread_flag(TIF_ISOLATE_BP_GUEST);
vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
if (rc == -EINTR) {
VCPU_EVENT(vcpu, 3, "%s", "machine check");
kvm_s390_reinject_machine_check(vcpu, &vsie_page->mcck_info);
return 0;
}
if (rc > 0)
rc = 0; /* we could still have an icpt */
else if (rc == -EFAULT)
return handle_fault(vcpu, vsie_page);
switch (scb_s->icptcode) {
case ICPT_INST:
if (scb_s->ipa == 0xb2b0)
rc = handle_stfle(vcpu, vsie_page);
break;
case ICPT_STOP:
/* stop not requested by g2 - must have been a kick */
if (!(atomic_read(&scb_o->cpuflags) & CPUSTAT_STOP_INT))
clear_vsie_icpt(vsie_page);
break;
case ICPT_VALIDITY:
if ((scb_s->ipa & 0xf000) != 0xf000)
scb_s->ipa += 0x1000;
break;
case ICPT_PARTEXEC:
if (scb_s->ipa == 0xb254)
rc = vsie_handle_mvpg(vcpu, vsie_page);
break;
}
return rc;
}
static void release_gmap_shadow(struct vsie_page *vsie_page)
{
if (vsie_page->gmap)
gmap_put(vsie_page->gmap);
WRITE_ONCE(vsie_page->gmap, NULL);
prefix_unmapped(vsie_page);
}
static int acquire_gmap_shadow(struct kvm_vcpu *vcpu,
struct vsie_page *vsie_page)
{
unsigned long asce;
union ctlreg0 cr0;
struct gmap *gmap;
int edat;
asce = vcpu->arch.sie_block->gcr[1];
cr0.val = vcpu->arch.sie_block->gcr[0];
edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
edat += edat && test_kvm_facility(vcpu->kvm, 78);
/*
* ASCE or EDAT could have changed since last icpt, or the gmap
* we're holding has been unshadowed. If the gmap is still valid,
* we can safely reuse it.
*/
if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat))
return 0;
/* release the old shadow - if any, and mark the prefix as unmapped */
release_gmap_shadow(vsie_page);
gmap = gmap_shadow(vcpu->arch.gmap, asce, edat);
if (IS_ERR(gmap))
return PTR_ERR(gmap);
gmap->private = vcpu->kvm;
WRITE_ONCE(vsie_page->gmap, gmap);
return 0;
}
/*
* Register the shadow scb at the VCPU, e.g. for kicking out of vsie.
*/
static void register_shadow_scb(struct kvm_vcpu *vcpu,
struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s);
/*
* External calls have to lead to a kick of the vcpu and
* therefore the vsie -> Simulate Wait state.
*/
kvm_s390_set_cpuflags(vcpu, CPUSTAT_WAIT);
/*
* We have to adjust the g3 epoch by the g2 epoch. The epoch will
* automatically be adjusted on tod clock changes via kvm_sync_clock.
*/
preempt_disable();
scb_s->epoch += vcpu->kvm->arch.epoch;
if (scb_s->ecd & ECD_MEF) {
scb_s->epdx += vcpu->kvm->arch.epdx;
if (scb_s->epoch < vcpu->kvm->arch.epoch)
scb_s->epdx += 1;
}
preempt_enable();
}
/*
* Unregister a shadow scb from a VCPU.
*/
static void unregister_shadow_scb(struct kvm_vcpu *vcpu)
{
kvm_s390_clear_cpuflags(vcpu, CPUSTAT_WAIT);
WRITE_ONCE(vcpu->arch.vsie_block, NULL);
}
/*
* Run the vsie on a shadowed scb, managing the gmap shadow, handling
* prefix pages and faults.
*
* Returns: - 0 if no errors occurred
* - > 0 if control has to be given to guest 2
* - -ENOMEM if out of memory
*/
static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
int rc = 0;
while (1) {
rc = acquire_gmap_shadow(vcpu, vsie_page);
if (!rc)
rc = map_prefix(vcpu, vsie_page);
if (!rc) {
gmap_enable(vsie_page->gmap);
update_intervention_requests(vsie_page);
rc = do_vsie_run(vcpu, vsie_page);
gmap_enable(vcpu->arch.gmap);
}
atomic_andnot(PROG_BLOCK_SIE, &scb_s->prog20);
if (rc == -EAGAIN)
rc = 0;
if (rc || scb_s->icptcode || signal_pending(current) ||
kvm_s390_vcpu_has_irq(vcpu, 0) ||
kvm_s390_vcpu_sie_inhibited(vcpu))
break;
cond_resched();
}
if (rc == -EFAULT) {
/*
* Addressing exceptions are always presentes as intercepts.
* As addressing exceptions are suppressing and our guest 3 PSW
* points at the responsible instruction, we have to
* forward the PSW and set the ilc. If we can't read guest 3
* instruction, we can use an arbitrary ilc. Let's always use
* ilen = 4 for now, so we can avoid reading in guest 3 virtual
* memory. (we could also fake the shadow so the hardware
* handles it).
*/
scb_s->icptcode = ICPT_PROGI;
scb_s->iprcc = PGM_ADDRESSING;
scb_s->pgmilc = 4;
scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, 4);
rc = 1;
}
return rc;
}
/*
* Get or create a vsie page for a scb address.
*
* Returns: - address of a vsie page (cached or new one)
* - NULL if the same scb address is already used by another VCPU
* - ERR_PTR(-ENOMEM) if out of memory
*/
static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
{
struct vsie_page *vsie_page;
struct page *page;
int nr_vcpus;
rcu_read_lock();
page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9);
rcu_read_unlock();
if (page) {
if (page_ref_inc_return(page) == 2)
return page_to_virt(page);
page_ref_dec(page);
}
/*
* We want at least #online_vcpus shadows, so every VCPU can execute
* the VSIE in parallel.
*/
nr_vcpus = atomic_read(&kvm->online_vcpus);
mutex_lock(&kvm->arch.vsie.mutex);
if (kvm->arch.vsie.page_count < nr_vcpus) {
page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO | GFP_DMA);
if (!page) {
mutex_unlock(&kvm->arch.vsie.mutex);
return ERR_PTR(-ENOMEM);
}
page_ref_inc(page);
kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page;
kvm->arch.vsie.page_count++;
} else {
/* reuse an existing entry that belongs to nobody */
while (true) {
page = kvm->arch.vsie.pages[kvm->arch.vsie.next];
if (page_ref_inc_return(page) == 2)
break;
page_ref_dec(page);
kvm->arch.vsie.next++;
kvm->arch.vsie.next %= nr_vcpus;
}
radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
}
page->index = addr;
/* double use of the same address */
if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) {
page_ref_dec(page);
mutex_unlock(&kvm->arch.vsie.mutex);
return NULL;
}
mutex_unlock(&kvm->arch.vsie.mutex);
vsie_page = page_to_virt(page);
memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block));
release_gmap_shadow(vsie_page);
vsie_page->fault_addr = 0;
vsie_page->scb_s.ihcpu = 0xffffU;
return vsie_page;
}
/* put a vsie page acquired via get_vsie_page */
static void put_vsie_page(struct kvm *kvm, struct vsie_page *vsie_page)
{
struct page *page = pfn_to_page(__pa(vsie_page) >> PAGE_SHIFT);
page_ref_dec(page);
}
int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu)
{
struct vsie_page *vsie_page;
unsigned long scb_addr;
int rc;
vcpu->stat.instruction_sie++;
if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIEF2))
return -EOPNOTSUPP;
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
BUILD_BUG_ON(sizeof(struct vsie_page) != PAGE_SIZE);
scb_addr = kvm_s390_get_base_disp_s(vcpu, NULL);
/* 512 byte alignment */
if (unlikely(scb_addr & 0x1ffUL))
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0) ||
kvm_s390_vcpu_sie_inhibited(vcpu))
return 0;
vsie_page = get_vsie_page(vcpu->kvm, scb_addr);
if (IS_ERR(vsie_page))
return PTR_ERR(vsie_page);
else if (!vsie_page)
/* double use of sie control block - simply do nothing */
return 0;
rc = pin_scb(vcpu, vsie_page, scb_addr);
if (rc)
goto out_put;
rc = shadow_scb(vcpu, vsie_page);
if (rc)
goto out_unpin_scb;
rc = pin_blocks(vcpu, vsie_page);
if (rc)
goto out_unshadow;
register_shadow_scb(vcpu, vsie_page);
rc = vsie_run(vcpu, vsie_page);
unregister_shadow_scb(vcpu);
unpin_blocks(vcpu, vsie_page);
out_unshadow:
unshadow_scb(vcpu, vsie_page);
out_unpin_scb:
unpin_scb(vcpu, vsie_page, scb_addr);
out_put:
put_vsie_page(vcpu->kvm, vsie_page);
return rc < 0 ? rc : 0;
}
/* Init the vsie data structures. To be called when a vm is initialized. */
void kvm_s390_vsie_init(struct kvm *kvm)
{
mutex_init(&kvm->arch.vsie.mutex);
INIT_RADIX_TREE(&kvm->arch.vsie.addr_to_page, GFP_KERNEL_ACCOUNT);
}
/* Destroy the vsie data structures. To be called when a vm is destroyed. */
void kvm_s390_vsie_destroy(struct kvm *kvm)
{
struct vsie_page *vsie_page;
struct page *page;
int i;
mutex_lock(&kvm->arch.vsie.mutex);
for (i = 0; i < kvm->arch.vsie.page_count; i++) {
page = kvm->arch.vsie.pages[i];
kvm->arch.vsie.pages[i] = NULL;
vsie_page = page_to_virt(page);
release_gmap_shadow(vsie_page);
/* free the radix tree entry */
radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
__free_page(page);
}
kvm->arch.vsie.page_count = 0;
mutex_unlock(&kvm->arch.vsie.mutex);
}
void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu)
{
struct kvm_s390_sie_block *scb = READ_ONCE(vcpu->arch.vsie_block);
/*
* Even if the VCPU lets go of the shadow sie block reference, it is
* still valid in the cache. So we can safely kick it.
*/
if (scb) {
atomic_or(PROG_BLOCK_SIE, &scb->prog20);
if (scb->prog0c & PROG_IN_SIE)
atomic_or(CPUSTAT_STOP_INT, &scb->cpuflags);
}
}
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