github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-30 18:13:41 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

KVM: nVMX: Check PAUSE_EXITING, not BUS_LOCK_DETECTION, on PAUSE emulation

Browse Source 
When emulating PAUSE on behalf of L2, check for interception in vmcs12 by
looking at primary execution controls, not secondary execution controls.
Checking for PAUSE_EXITING in secondary execution controls effectively
results in KVM looking for BUS_LOCK_DETECTION, which KVM doesn't expose to
L1, i.e. is always off in vmcs12, and ultimately results in KVM failing to
"intercept" PAUSE.

Because KVM doesn't handle interception during emulation correctly on VMX,
i.e. the "fixed" code is still quite broken, and not intercepting PAUSE is
relatively benign, for all intents and purposes the bug means that L2 gets
to live when it would otherwise get an unexpected #UD.

Fixes: 4984563823 ("KVM: nVMX: Emulate NOPs in L2, and PAUSE if it's not intercepted")
Link: https://lore.kernel.org/r/20250201015518.689704-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2025-01-31 17:55:08 -08:00
parent 93da6af3ae
commit f002a97ec8
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/kvm/vmx/vmx.c
View File

@ -8092,7 +8092,7 @@ int vmx_check_intercept(struct kvm_vcpu *vcpu,
* the PAUSE.
*/
if ((info->rep_prefix != REPE_PREFIX) ||
!nested_cpu_has2(vmcs12, CPU_BASED_PAUSE_EXITING))
!nested_cpu_has(vmcs12, CPU_BASED_PAUSE_EXITING))
return X86EMUL_CONTINUE;
break;