KVM was incorrectly checking vmcs12->host_ia32_efer even if the "load
IA32_EFER" exit control was reset. Also, some checks were not using
the new CC macro for tracing.
Cleanup everything so that the vCPU's 64-bit mode is determined
directly from EFER_LMA and the VMCS checks are based on that, which
matches section 26.2.4 of the SDM.
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Fixes: 5845038c11
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The following was reported on i386:
arch/x86/kvm/vmx/vmx.c: In function 'hv_enable_direct_tlbflush':
arch/x86/kvm/vmx/vmx.c:503:10: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
pr_debugs() in this function are more or less useless, let's just
remove them. evmcs->hv_vm_id can use 'unsigned long' instead of 'u64'.
Also, simplify the code a little bit.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that VMREAD flows require a taken branch, courtesy of commit
3901336ed9 ("x86/kvm: Don't call kvm_spurious_fault() from .fixup")
bite the bullet and add full error handling to VMREAD, i.e. replace the
JMP added by __ex()/____kvm_handle_fault_on_reboot() with a hinted Jcc.
To minimize the code footprint, add a helper function, vmread_error(),
to handle both faults and failures so that the inline flow has a single
CALL.
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Rework the VMX instruction helpers using asm-goto to branch directly
to error/fault "handlers" in lieu of using __ex(), i.e. the generic
____kvm_handle_fault_on_reboot(). Branching directly to fault handling
code during fixup avoids the extra JMP that is inserted after every VMX
instruction when using the generic "fault on reboot" (see commit
3901336ed9, "x86/kvm: Don't call kvm_spurious_fault() from .fixup").
Opportunistically clean up the helpers so that they all have consistent
error handling and messages.
Leave the usage of ____kvm_handle_fault_on_reboot() (via __ex()) in
kvm_cpu_vmxoff() and nested_vmx_check_vmentry_hw() as is. The VMXOFF
case is not a fast path, i.e. the cleanliness of __ex() is worth the
JMP, and the extra JMP in nested_vmx_check_vmentry_hw() is unavoidable.
Note, VMREAD cannot get the asm-goto treatment as output operands aren't
compatible with GCC's asm-goto due to internal compiler restrictions.
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Explicitly check kvm_rebooting in kvm_spurious_fault() prior to invoking
BUG(), as opposed to assuming the caller has already done so. Letting
kvm_spurious_fault() be called "directly" will allow VMX to better
optimize its low level assembly flows.
As a happy side effect, kvm_spurious_fault() no longer needs to be
marked as a dead end since it doesn't unconditionally BUG().
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Allowing an unlimited number of MSRs to be specified via the VMX
load/store MSR lists (e.g., vm-entry MSR load list) is bad for two
reasons. First, a guest can specify an unreasonable number of MSRs,
forcing KVM to process all of them in software. Second, the SDM bounds
the number of MSRs allowed to be packed into the atomic switch MSR lists.
Quoting the "Miscellaneous Data" section in the "VMX Capability
Reporting Facility" appendix:
"Bits 27:25 is used to compute the recommended maximum number of MSRs
that should appear in the VM-exit MSR-store list, the VM-exit MSR-load
list, or the VM-entry MSR-load list. Specifically, if the value bits
27:25 of IA32_VMX_MISC is N, then 512 * (N + 1) is the recommended
maximum number of MSRs to be included in each list. If the limit is
exceeded, undefined processor behavior may result (including a machine
check during the VMX transition)."
Because KVM needs to protect itself and can't model "undefined processor
behavior", arbitrarily force a VM-entry to fail due to MSR loading when
the MSR load list is too large. Similarly, trigger an abort during a VM
exit that encounters an MSR load list or MSR store list that is too large.
The MSR list size is intentionally not pre-checked so as to maintain
compatibility with hardware inasmuch as possible.
Test these new checks with the kvm-unit-test "x86: nvmx: test max atomic
switch MSRs".
Suggested-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Marc Orr <marcorr@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The RDPRU instruction gives the guest read access to the IA32_APERF
MSR and the IA32_MPERF MSR. According to volume 3 of the APM, "When
virtualization is enabled, this instruction can be intercepted by the
Hypervisor. The intercept bit is at VMCB byte offset 10h, bit 14."
Since we don't enumerate the instruction in KVM_SUPPORTED_CPUID,
intercept it and synthesize #UD.
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Drew Schmitt <dasch@google.com>
Reviewed-by: Jacob Xu <jacobhxu@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
According to the Intel SDM, volume 2, "CPUID," the index is
significant (or partially significant) for CPUID leaves 0FH, 10H, 12H,
17H, 18H, and 1FH.
Add the corresponding flag to these CPUID leaves in do_host_cpuid().
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Steve Rutherford <srutherford@google.com>
Fixes: a87f2d3a6e ("KVM: x86: Add Intel CPUID.1F cpuid emulation support")
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Do not skip invalid shadow pages when zapping obsolete pages if the
pages' root_count has reached zero, in which case the page can be
immediately zapped and freed.
Update the comment accordingly.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Toggle mmu_valid_gen between '0' and '1' instead of blindly incrementing
the generation. Because slots_lock is held for the entire duration of
zapping obsolete pages, it's impossible for there to be multiple invalid
generations associated with shadow pages at any given time.
Toggling between the two generations (valid vs. invalid) allows changing
mmu_valid_gen from an unsigned long to a u8, which reduces the size of
struct kvm_mmu_page from 160 to 152 bytes on 64-bit KVM, i.e. reduces
KVM's memory footprint by 8 bytes per shadow page.
Set sp->mmu_valid_gen before it is added to active_mmu_pages.
Functionally this has no effect as kvm_mmu_alloc_page() has a single
caller that sets sp->mmu_valid_gen soon thereafter, but visually it is
jarring to see a shadow page being added to the list without its
mmu_valid_gen first being set.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that the fast invalidate mechanism has been reintroduced, restore
the performance tweaks for fast invalidation that existed prior to its
removal.
Paraphrasing the original changelog (commit 5ff0568374 was itself a
partial revert):
Don't force reloading the remote mmu when zapping an obsolete page, as
a MMU_RELOAD request has already been issued by kvm_mmu_zap_all_fast()
immediately after incrementing mmu_valid_gen, i.e. after marking pages
obsolete.
This reverts commit 5ff0568374.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that the fast invalidate mechanism has been reintroduced, restore
the performance tweaks for fast invalidation that existed prior to its
removal.
Paraphrashing the original changelog:
Reload the mmu on all vCPUs after updating the generation number so
that obsolete pages are not used by any vCPUs. This allows collapsing
all TLB flushes during obsolete page zapping into a single flush, as
there is no need to flush when dropping mmu_lock (to reschedule).
Note: a remote TLB flush is still needed before freeing the pages as
other vCPUs may be doing a lockless shadow page walk.
Opportunstically improve the comments restored by the revert (the
code itself is a true revert).
This reverts commit f34d251d66.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that the fast invalidate mechanism has been reintroduced, restore
the performance tweaks for fast invalidation that existed prior to its
removal.
Paraphrashing the original changelog:
Zap at least 10 shadow pages before releasing mmu_lock to reduce the
overhead associated with re-acquiring the lock.
Note: "10" is an arbitrary number, speculated to be high enough so
that a vCPU isn't stuck zapping obsolete pages for an extended period,
but small enough so that other vCPUs aren't starved waiting for
mmu_lock.
This reverts commit 43d2b14b10.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that the fast invalidate mechanism has been reintroduced, restore
the tracepoint associated with said mechanism.
Note, the name of the tracepoint deviates from the original tracepoint
so as to match KVM's current nomenclature.
This reverts commit 42560fb1f3.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that the fast invalidate mechanism has been reintroduced, restore
tracing of the generation number in shadow page tracepoints.
This reverts commit b59c4830ca.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Use the fast invalidate mechasim to zap MMIO sptes on a MMIO generation
wrap. The fast invalidate flow was reintroduced to fix a livelock bug
in kvm_mmu_zap_all() that can occur if kvm_mmu_zap_all() is invoked when
the guest has live vCPUs. I.e. using kvm_mmu_zap_all() to handle the
MMIO generation wrap is theoretically susceptible to the livelock bug.
This effectively reverts commit 4771450c34 ("Revert "KVM: MMU: drop
kvm_mmu_zap_mmio_sptes""), i.e. restores the behavior of commit
a8eca9dcc6 ("KVM: MMU: drop kvm_mmu_zap_mmio_sptes").
Note, this actually fixes commit 571c5af06e ("KVM: x86/mmu:
Voluntarily reschedule as needed when zapping MMIO sptes"), but there
is no need to incrementally revert back to using fast invalidate, e.g.
doing so doesn't provide any bisection or stability benefits.
Fixes: 571c5af06e ("KVM: x86/mmu: Voluntarily reschedule as needed when zapping MMIO sptes")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Treat invalid shadow pages as obsolete to fix a bug where an obsolete
and invalid page with a non-zero root count could become non-obsolete
due to mmu_valid_gen wrapping. The bug is largely theoretical with the
current code base, as an unsigned long will effectively never wrap on
64-bit KVM, and userspace would have to deliberately stall a vCPU in
order to keep an obsolete invalid page on the active list while
simultaneously modifying memslots billions of times to trigger a wrap.
The obvious alternative is to use a 64-bit value for mmu_valid_gen,
but it's actually desirable to go in the opposite direction, i.e. using
a smaller 8-bit value to reduce KVM's memory footprint by 8 bytes per
shadow page, and relying on proper treatment of invalid pages instead of
preventing the generation from wrapping.
Note, "Fixes" points at a commit that was at one point reverted, but has
since been restored.
Fixes: 5304b8d37c ("KVM: MMU: fast invalidate all pages")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Filter out drastic fluctuation and random fluctuation, remove
timer_advance_adjust_done altogether, the adjustment would be
continuous.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
As the latest Intel 64 and IA-32 Architectures Software Developer's
Manual, UMWAIT and TPAUSE instructions cause a VM exit if the
RDTSC exiting and enable user wait and pause VM-execution
controls are both 1.
Because KVM never enable RDTSC exiting, the vm-exit for UMWAIT and TPAUSE
should never happen. Considering EXIT_REASON_XSAVES and
EXIT_REASON_XRSTORS is also unexpected VM-exit for KVM. Introduce a common
exit helper handle_unexpected_vmexit() to handle these unexpected VM-exit.
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Tao Xu <tao3.xu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
UMWAIT and TPAUSE instructions use 32bit IA32_UMWAIT_CONTROL at MSR index
E1H to determines the maximum time in TSC-quanta that the processor can
reside in either C0.1 or C0.2.
This patch emulates MSR IA32_UMWAIT_CONTROL in guest and differentiate
IA32_UMWAIT_CONTROL between host and guest. The variable
mwait_control_cached in arch/x86/kernel/cpu/umwait.c caches the MSR value,
so this patch uses it to avoid frequently rdmsr of IA32_UMWAIT_CONTROL.
Co-developed-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Tao Xu <tao3.xu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
UMONITOR, UMWAIT and TPAUSE are a set of user wait instructions.
This patch adds support for user wait instructions in KVM. Availability
of the user wait instructions is indicated by the presence of the CPUID
feature flag WAITPKG CPUID.0x07.0x0:ECX[5]. User wait instructions may
be executed at any privilege level, and use 32bit IA32_UMWAIT_CONTROL MSR
to set the maximum time.
The behavior of user wait instructions in VMX non-root operation is
determined first by the setting of the "enable user wait and pause"
secondary processor-based VM-execution control bit 26.
If the VM-execution control is 0, UMONITOR/UMWAIT/TPAUSE cause
an invalid-opcode exception (#UD).
If the VM-execution control is 1, treatment is based on the
setting of the “RDTSC exiting†VM-execution control. Because KVM never
enables RDTSC exiting, if the instruction causes a delay, the amount of
time delayed is called here the physical delay. The physical delay is
first computed by determining the virtual delay. If
IA32_UMWAIT_CONTROL[31:2] is zero, the virtual delay is the value in
EDX:EAX minus the value that RDTSC would return; if
IA32_UMWAIT_CONTROL[31:2] is not zero, the virtual delay is the minimum
of that difference and AND(IA32_UMWAIT_CONTROL,FFFFFFFCH).
Because umwait and tpause can put a (psysical) CPU into a power saving
state, by default we dont't expose it to kvm and enable it only when
guest CPUID has it.
Detailed information about user wait instructions can be found in the
latest Intel 64 and IA-32 Architectures Software Developer's Manual.
Co-developed-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Tao Xu <tao3.xu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
VMX's EPT misconfig flow to handle fast-MMIO path falls back to decoding
the instruction to determine the instruction length when running as a
guest (Hyper-V doesn't fill VMCS.VM_EXIT_INSTRUCTION_LEN because it's
technically not defined for EPT misconfigs). Rather than implement the
slow skip in VMX's generic skip_emulated_instruction(),
handle_ept_misconfig() directly calls kvm_emulate_instruction() with
EMULTYPE_SKIP, which intentionally doesn't do single-step detection, and
so handle_ept_misconfig() misses a single-step #DB.
Rework the EPT misconfig fallback case to route it through
kvm_skip_emulated_instruction() so that single-step #DBs and interrupt
shadow updates are handled automatically. I.e. make VMX's slow skip
logic match SVM's and have the SVM flow not intentionally avoid the
shadow update.
Alternatively, the handle_ept_misconfig() could manually handle single-
step detection, but that results in EMULTYPE_SKIP having split logic for
the interrupt shadow vs. single-step #DBs, and split emulator logic is
largely what led to this mess in the first place.
Modifying SVM to mirror VMX flow isn't really an option as SVM's case
isn't limited to a specific exit reason, i.e. handling the slow skip in
skip_emulated_instruction() is mandatory for all intents and purposes.
Drop VMX's skip_emulated_instruction() wrapper since it can now fail,
and instead WARN if it fails unexpectedly, e.g. if exit_reason somehow
becomes corrupted.
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Fixes: d391f12070 ("x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Deferring emulation failure handling (in some cases) to the caller of
x86_emulate_instruction() has proven fragile, e.g. multiple instances of
KVM not setting run->exit_reason on EMULATE_FAIL, largely due to it
being difficult to discern what emulation types can return what result,
and which combination of types and results are handled where.
Now that x86_emulate_instruction() always handles emulation failure,
i.e. EMULATION_FAIL is only referenced in callers, remove the
emulation_result enums entirely. Per KVM's existing exit handling
conventions, return '0' and '1' for "exit to userspace" and "resume
guest" respectively. Doing so cleans up many callers, e.g. they can
return kvm_emulate_instruction() directly instead of having to interpret
its result.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that EMULATE_FAIL is completely unused, remove the last remaning
usage where KVM does something functional in response to EMULATE_FAIL.
Leave the check in place as a WARN_ON_ONCE to provide a better paper
trail when EMULATE_{DONE,FAIL,USER_EXIT} are completely removed.
Opportunistically remove the gotos in handle_invalid_guest_state().
With the EMULATE_FAIL handling gone there is no need to have a common
handler for emulation failure and the gotos only complicate things,
e.g. the signal_pending() check always returns '1', but this is far
from obvious when glancing through the code.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Request triple fault in kvm_inject_realmode_interrupt() instead of
returning EMULATE_FAIL and deferring to the caller. All existing
callers request triple fault and it's highly unlikely Real Mode is
going to acquire new features. While this consolidates a small amount
of code, the real goal is to remove the last reference to EMULATE_FAIL.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Consolidate the reporting of emulation failure into kvm_task_switch()
so that it can return EMULATE_USER_EXIT. This helps pave the way for
removing EMULATE_FAIL altogether.
This also fixes a theoretical bug where task switch interception could
suppress an EMULATE_USER_EXIT return.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Kill a few birds with one stone by forcing an exit to userspace on skip
emulation failure. This removes a reference to EMULATE_FAIL, fixes a
bug in handle_ept_misconfig() where it would exit to userspace without
setting run->exit_reason, and fixes a theoretical bug in SVM's
task_switch_interception() where it would overwrite run->exit_reason on
a return of EMULATE_USER_EXIT.
Note, this technically doesn't fully fix task_switch_interception()
as it now incorrectly handles EMULATE_FAIL, but in practice there is no
bug as EMULATE_FAIL will never be returned for EMULTYPE_SKIP.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Immediately inject a #UD and return EMULATE done if emulation fails when
handling an intercepted #UD. This helps pave the way for removing
EMULATE_FAIL altogether.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add an explicit emulation type for forced #UD emulation and use it to
detect that KVM should unconditionally inject a #UD instead of falling
into its standard emulation failure handling.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Immediately inject a #GP when VMware emulation fails and return
EMULATE_DONE instead of propagating EMULATE_FAIL up the stack. This
helps pave the way for removing EMULATE_FAIL altogether.
Rename EMULTYPE_VMWARE to EMULTYPE_VMWARE_GP to document that the x86
emulator is called to handle VMware #GP interception, e.g. why a #GP
is injected on emulation failure for EMULTYPE_VMWARE_GP.
Drop EMULTYPE_NO_UD_ON_FAIL as a standalone type. The "no #UD on fail"
is used only in the VMWare case and is obsoleted by having the emulator
itself reinject #GP.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The VMware backdoor hooks #GP faults on IN{S}, OUT{S}, and RDPMC, none
of which generate a non-zero error code for their #GP. Re-injecting #GP
instead of attempting emulation on a non-zero error code will allow a
future patch to move #GP injection (for emulation failure) into
kvm_emulate_instruction() without having to plumb in the error code.
Reviewed-and-tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Return the single-step emulation result directly instead of via an out
param. Presumably at some point in the past kvm_vcpu_do_singlestep()
could be called with *r==EMULATE_USER_EXIT, but that is no longer the
case, i.e. all callers are happy to overwrite their own return variable.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When handling emulation failure, return the emulation result directly
instead of capturing it in a local variable. Future patches will move
additional cases into handle_emulation_failure(), clean up the cruft
before so there isn't an ugly mix of setting a local variable and
returning directly.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move the stat.mmio_exits update into x86_emulate_instruction(). This is
both a bug fix, e.g. the current update flows will incorrectly increment
mmio_exits on emulation failure, and a preparatory change to set the
stage for eliminating EMULATE_DONE and company.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
According to section "Checks Related to Address-Space Size" in Intel SDM
vol 3C, the following checks are performed on vmentry of nested guests:
If the logical processor is outside IA-32e mode (if IA32_EFER.LMA = 0)
at the time of VM entry, the following must hold:
- The "IA-32e mode guest" VM-entry control is 0.
- The "host address-space size" VM-exit control is 0.
If the logical processor is in IA-32e mode (if IA32_EFER.LMA = 1) at the
time of VM entry, the "host address-space size" VM-exit control must be 1.
If the "host address-space size" VM-exit control is 0, the following must
hold:
- The "IA-32e mode guest" VM-entry control is 0.
- Bit 17 of the CR4 field (corresponding to CR4.PCIDE) is 0.
- Bits 63:32 in the RIP field are 0.
If the "host address-space size" VM-exit control is 1, the following must
hold:
- Bit 5 of the CR4 field (corresponding to CR4.PAE) is 1.
- The RIP field contains a canonical address.
On processors that do not support Intel 64 architecture, checks are
performed to ensure that the "IA-32e mode guest" VM-entry control and the
"host address-space size" VM-exit control are both 0.
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Hyper-V 2019 doesn't expose MD_CLEAR CPUID bit to guests when it cannot
guarantee that two virtual processors won't end up running on sibling SMT
threads without knowing about it. This is done as an optimization as in
this case there is nothing the guest can do to protect itself against MDS
and issuing additional flush requests is just pointless. On bare metal the
topology is known, however, when Hyper-V is running nested (e.g. on top of
KVM) it needs an additional piece of information: a confirmation that the
exposed topology (wrt vCPU placement on different SMT threads) is
trustworthy.
NoNonArchitecturalCoreSharing (CPUID 0x40000004 EAX bit 18) is described in
TLFS as follows: "Indicates that a virtual processor will never share a
physical core with another virtual processor, except for virtual processors
that are reported as sibling SMT threads." From KVM we can give such
guarantee in two cases:
- SMT is unsupported or forcefully disabled (just 'disabled' doesn't work
as it can become re-enabled during the lifetime of the guest).
- vCPUs are properly pinned so the scheduler won't put them on sibling
SMT threads (when they're not reported as such).
This patch reports NoNonArchitecturalCoreSharing bit in to userspace in the
first case. The second case is outside of KVM's domain of responsibility
(as vCPU pinning is actually done by someone who manages KVM's userspace -
e.g. libvirt pinning QEMU threads).
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reported by syzkaller:
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
RIP: 0010:__apic_accept_irq+0x46/0x740 arch/x86/kvm/lapic.c:1029
Call Trace:
kvm_apic_set_irq+0xb4/0x140 arch/x86/kvm/lapic.c:558
stimer_notify_direct arch/x86/kvm/hyperv.c:648 [inline]
stimer_expiration arch/x86/kvm/hyperv.c:659 [inline]
kvm_hv_process_stimers+0x594/0x1650 arch/x86/kvm/hyperv.c:686
vcpu_enter_guest+0x2b2a/0x54b0 arch/x86/kvm/x86.c:7896
vcpu_run+0x393/0xd40 arch/x86/kvm/x86.c:8152
kvm_arch_vcpu_ioctl_run+0x636/0x900 arch/x86/kvm/x86.c:8360
kvm_vcpu_ioctl+0x6cf/0xaf0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2765
The testcase programs HV_X64_MSR_STIMERn_CONFIG/HV_X64_MSR_STIMERn_COUNT,
in addition, there is no lapic in the kernel, the counters value are small
enough in order that kvm_hv_process_stimers() inject this already-expired
timer interrupt into the guest through lapic in the kernel which triggers
the NULL deferencing. This patch fixes it by don't advertise direct mode
synthetic timers and discarding the inject when lapic is not in kernel.
syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=1752fe0a600000
Reported-by: syzbot+dff25ee91f0c7d5c1695@syzkaller.appspotmail.com
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Zapping collapsible sptes, a.k.a. 4k sptes that can be promoted into a
large page, is only necessary when changing only the dirty logging flag
of a memory region. If the memslot is also being moved, then all sptes
for the memslot are zapped when it is invalidated. When a memslot is
being created, it is impossible for there to be existing dirty mappings,
e.g. KVM can have MMIO sptes, but not present, and thus dirty, sptes.
Note, the comment and logic are shamelessly borrowed from MIPS's version
of kvm_arch_commit_memory_region().
Fixes: 3ea3b7fa9a ("kvm: mmu: lazy collapse small sptes into large sptes")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
It was discovered that after commit 65efa61dc0 ("selftests: kvm: provide
common function to enable eVMCS") hyperv_cpuid selftest is failing on AMD.
The reason is that the commit changed _vcpu_ioctl() to vcpu_ioctl() in the
test and this one can't fail.
Instead of fixing the test is seems to make more sense to not announce
KVM_CAP_HYPERV_ENLIGHTENED_VMCS support if it is definitely missing
(on svm and in case kvm_intel.nested=0).
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since commit 5158917c7b ("KVM: x86: nVMX: Allow nested_enable_evmcs to
be NULL") the code in x86.c is prepared to see nested_enable_evmcs being
NULL and in VMX case it actually is when nesting is disabled. Remove the
unneeded stub from SVM code.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Hyper-V provides direct tlb flush function which helps
L1 Hypervisor to handle Hyper-V tlb flush request from
L2 guest. Add the function support for VMX.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Hyper-V direct tlb flush function should be enabled for
guest that only uses Hyper-V hypercall. User space
hypervisor(e.g, Qemu) can disable KVM identification in
CPUID and just exposes Hyper-V identification to make
sure the precondition. Add new KVM capability KVM_CAP_
HYPERV_DIRECT_TLBFLUSH for user space to enable Hyper-V
direct tlb function and this function is default to be
disabled in KVM.
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
These MSRs should be enumerated by KVM_GET_MSR_INDEX_LIST, so that
userspace knows that these MSRs may be part of the vCPU state.
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Eric Hankland <ehankland@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* ARM: ITS translation cache; support for 512 vCPUs, various cleanups
and bugfixes
* PPC: various minor fixes and preparation
* x86: bugfixes all over the place (posted interrupts, SVM, emulation
corner cases, blocked INIT), some IPI optimizations
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"s390:
- ioctl hardening
- selftests
ARM:
- ITS translation cache
- support for 512 vCPUs
- various cleanups and bugfixes
PPC:
- various minor fixes and preparation
x86:
- bugfixes all over the place (posted interrupts, SVM, emulation
corner cases, blocked INIT)
- some IPI optimizations"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (75 commits)
KVM: X86: Use IPI shorthands in kvm guest when support
KVM: x86: Fix INIT signal handling in various CPU states
KVM: VMX: Introduce exit reason for receiving INIT signal on guest-mode
KVM: VMX: Stop the preemption timer during vCPU reset
KVM: LAPIC: Micro optimize IPI latency
kvm: Nested KVM MMUs need PAE root too
KVM: x86: set ctxt->have_exception in x86_decode_insn()
KVM: x86: always stop emulation on page fault
KVM: nVMX: trace nested VM-Enter failures detected by H/W
KVM: nVMX: add tracepoint for failed nested VM-Enter
x86: KVM: svm: Fix a check in nested_svm_vmrun()
KVM: x86: Return to userspace with internal error on unexpected exit reason
KVM: x86: Add kvm_emulate_{rd,wr}msr() to consolidate VXM/SVM code
KVM: x86: Refactor up kvm_{g,s}et_msr() to simplify callers
doc: kvm: Fix return description of KVM_SET_MSRS
KVM: X86: Tune PLE Window tracepoint
KVM: VMX: Change ple_window type to unsigned int
KVM: X86: Remove tailing newline for tracepoints
KVM: X86: Trace vcpu_id for vmexit
KVM: x86: Manually calculate reserved bits when loading PDPTRS
...
Pull core timer updates from Thomas Gleixner:
"Timers and timekeeping updates:
- A large overhaul of the posix CPU timer code which is a preparation
for moving the CPU timer expiry out into task work so it can be
properly accounted on the task/process.
An update to the bogus permission checks will come later during the
merge window as feedback was not complete before heading of for
travel.
- Switch the timerqueue code to use cached rbtrees and get rid of the
homebrewn caching of the leftmost node.
- Consolidate hrtimer_init() + hrtimer_init_sleeper() calls into a
single function
- Implement the separation of hrtimers to be forced to expire in hard
interrupt context even when PREEMPT_RT is enabled and mark the
affected timers accordingly.
- Implement a mechanism for hrtimers and the timer wheel to protect
RT against priority inversion and live lock issues when a (hr)timer
which should be canceled is currently executing the callback.
Instead of infinitely spinning, the task which tries to cancel the
timer blocks on a per cpu base expiry lock which is held and
released by the (hr)timer expiry code.
- Enable the Hyper-V TSC page based sched_clock for Hyper-V guests
resulting in faster access to timekeeping functions.
- Updates to various clocksource/clockevent drivers and their device
tree bindings.
- The usual small improvements all over the place"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
posix-cpu-timers: Fix permission check regression
posix-cpu-timers: Always clear head pointer on dequeue
hrtimer: Add a missing bracket and hide `migration_base' on !SMP
posix-cpu-timers: Make expiry_active check actually work correctly
posix-timers: Unbreak CONFIG_POSIX_TIMERS=n build
tick: Mark sched_timer to expire in hard interrupt context
hrtimer: Add kernel doc annotation for HRTIMER_MODE_HARD
x86/hyperv: Hide pv_ops access for CONFIG_PARAVIRT=n
posix-cpu-timers: Utilize timerqueue for storage
posix-cpu-timers: Move state tracking to struct posix_cputimers
posix-cpu-timers: Deduplicate rlimit handling
posix-cpu-timers: Remove pointless comparisons
posix-cpu-timers: Get rid of 64bit divisions
posix-cpu-timers: Consolidate timer expiry further
posix-cpu-timers: Get rid of zero checks
rlimit: Rewrite non-sensical RLIMIT_CPU comment
posix-cpu-timers: Respect INFINITY for hard RTTIME limit
posix-cpu-timers: Switch thread group sampling to array
posix-cpu-timers: Restructure expiry array
posix-cpu-timers: Remove cputime_expires
...
James Harvey reported a livelock that was introduced by commit
d012a06ab1 ("Revert "KVM: x86/mmu: Zap only the relevant pages when
removing a memslot"").
The livelock occurs because kvm_mmu_zap_all() as it exists today will
voluntarily reschedule and drop KVM's mmu_lock, which allows other vCPUs
to add shadow pages. With enough vCPUs, kvm_mmu_zap_all() can get stuck
in an infinite loop as it can never zap all pages before observing lock
contention or the need to reschedule. The equivalent of kvm_mmu_zap_all()
that was in use at the time of the reverted commit (4e103134b8, "KVM:
x86/mmu: Zap only the relevant pages when removing a memslot") employed
a fast invalidate mechanism and was not susceptible to the above livelock.
There are three ways to fix the livelock:
- Reverting the revert (commit d012a06ab1) is not a viable option as
the revert is needed to fix a regression that occurs when the guest has
one or more assigned devices. It's unlikely we'll root cause the device
assignment regression soon enough to fix the regression timely.
- Remove the conditional reschedule from kvm_mmu_zap_all(). However, although
removing the reschedule would be a smaller code change, it's less safe
in the sense that the resulting kvm_mmu_zap_all() hasn't been used in
the wild for flushing memslots since the fast invalidate mechanism was
introduced by commit 6ca18b6950 ("KVM: x86: use the fast way to
invalidate all pages"), back in 2013.
- Reintroduce the fast invalidate mechanism and use it when zapping shadow
pages in response to a memslot being deleted/moved, which is what this
patch does.
For all intents and purposes, this is a revert of commit ea145aacf4
("Revert "KVM: MMU: fast invalidate all pages"") and a partial revert of
commit 7390de1e99 ("Revert "KVM: x86: use the fast way to invalidate
all pages""), i.e. restores the behavior of commit 5304b8d37c ("KVM:
MMU: fast invalidate all pages") and commit 6ca18b6950 ("KVM: x86:
use the fast way to invalidate all pages") respectively.
Fixes: d012a06ab1 ("Revert "KVM: x86/mmu: Zap only the relevant pages when removing a memslot"")
Reported-by: James Harvey <jamespharvey20@gmail.com>
Cc: Alex Willamson <alex.williamson@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Emulation of VMPTRST can incorrectly inject a page fault
when passed an operand that points to an MMIO address.
The page fault will use uninitialized kernel stack memory
as the CR2 and error code.
The right behavior would be to abort the VM with a KVM_EXIT_INTERNAL_ERROR
exit to userspace; however, it is not an easy fix, so for now just ensure
that the error code and CR2 are zero.
Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
Cc: stable@vger.kernel.org
[add comment]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The implementation of vmread to memory is still incomplete, as it
lacks the ability to do vmread to I/O memory just like vmptrst.
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit cd7764fe9f ("KVM: x86: latch INITs while in system management mode")
changed code to latch INIT while vCPU is in SMM and process latched INIT
when leaving SMM. It left a subtle remark in commit message that similar
treatment should also be done while vCPU is in VMX non-root-mode.
However, INIT signals should actually be latched in various vCPU states:
(*) For both Intel and AMD, INIT signals should be latched while vCPU
is in SMM.
(*) For Intel, INIT should also be latched while vCPU is in VMX
operation and later processed when vCPU leaves VMX operation by
executing VMXOFF.
(*) For AMD, INIT should also be latched while vCPU runs with GIF=0
or in guest-mode with intercept defined on INIT signal.
To fix this:
1) Add kvm_x86_ops->apic_init_signal_blocked() such that each CPU vendor
can define the various CPU states in which INIT signals should be
blocked and modify kvm_apic_accept_events() to use it.
2) Modify vmx_check_nested_events() to check for pending INIT signal
while vCPU in guest-mode. If so, emualte vmexit on
EXIT_REASON_INIT_SIGNAL. Note that nSVM should have similar behaviour
but is currently left as a TODO comment to implement in the future
because nSVM don't yet implement svm_check_nested_events().
Note: Currently KVM nVMX implementation don't support VMX wait-for-SIPI
activity state as specified in MSR_IA32_VMX_MISC bits 6:8 exposed to
guest (See nested_vmx_setup_ctls_msrs()).
If and when support for this activity state will be implemented,
kvm_check_nested_events() would need to avoid emulating vmexit on
INIT signal in case activity-state is wait-for-SIPI. In addition,
kvm_apic_accept_events() would need to be modified to avoid discarding
SIPI in case VMX activity-state is wait-for-SIPI but instead delay
SIPI processing to vmx_check_nested_events() that would clear
pending APIC events and emulate vmexit on SIPI.
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Co-developed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The hrtimer which is used to emulate lapic timer is stopped during
vcpu reset, preemption timer should do the same.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
