github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-01 02:53:36 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

KVM: nVMX: Allow emulating RDPID on behalf of L2

Browse Source 
Return X86EMUL_CONTINUE instead X86EMUL_UNHANDLEABLE when emulating RDPID
on behalf of L2 and L1 _does_ expose RDPID/RDTSCP to L2.  When RDPID
emulation was added by commit fb6d4d340e ("KVM: x86: emulate RDPID"),
KVM incorrectly allowed emulation by default.  Commit 07721feee4 ("KVM:
nVMX: Don't emulate instructions in guest mode") fixed that flaw, but
missed that RDPID emulation was relying on the common return path to allow
emulation on behalf of L2.

Fixes: 07721feee4 ("KVM: nVMX: Don't emulate instructions in guest mode")
Link: https://lore.kernel.org/r/20250201015518.689704-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2025-01-31 17:55:10 -08:00
parent c8e612bfed
commit 3244616aac
1 changed files with 7 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
arch/x86/kvm/vmx/vmx.c
View File

@ -8049,18 +8049,19 @@ int vmx_check_intercept(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
switch (info->intercept) {
/*
* RDPID causes #UD if disabled through secondary execution controls.
* Because it is marked as EmulateOnUD, we need to intercept it here.
* Note, RDPID is hidden behind ENABLE_RDTSCP.
*/
case x86_intercept_rdpid:
/*
* RDPID causes #UD if not enabled through secondary execution
* controls (ENABLE_RDTSCP). Note, the implicit MSR access to
* TSC_AUX is NOT subject to interception, i.e. checking only
* the dedicated execution control is architecturally correct.
*/
if (!nested_cpu_has2(vmcs12, SECONDARY_EXEC_ENABLE_RDTSCP)) {
exception->vector = UD_VECTOR;
exception->error_code_valid = false;
return X86EMUL_PROPAGATE_FAULT;
}
break;
return X86EMUL_CONTINUE;
case x86_intercept_in:
case x86_intercept_ins: