Messages in this thread Patch in this message | | | From | Sean Christopherson <> | Subject | [PATCH 1/6] KVM: x86: Fix tracing of CPUID.function when function is out-of-range | Date | Mon, 2 Mar 2020 11:57:31 -0800 |
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Rework kvm_cpuid() to query entry->function when adjusting the output values so that the original function (in the aptly named "function") is preserved for tracing. This fixes a bug where trace_kvm_cpuid() will trace the max function for a range instead of the requested function if the requested function is out-of-range and an entry for the max function exists.
Fixes: 43561123ab37 ("kvm: x86: Improve emulation of CPUID leaves 0BH and 1FH") Reported-by: Jan Kiszka <jan.kiszka@siemens.com> Cc: Jim Mattson <jmattson@google.com> Cc: Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> --- arch/x86/kvm/cpuid.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index b1c469446b07..6be012937eba 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -997,12 +997,12 @@ static bool cpuid_function_in_range(struct kvm_vcpu *vcpu, u32 function) return max && function <= max->eax; } +/* Returns true if the requested leaf/function exists in guest CPUID. */ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx, bool check_limit) { - u32 function = *eax, index = *ecx; + const u32 function = *eax, index = *ecx; struct kvm_cpuid_entry2 *entry; - struct kvm_cpuid_entry2 *max; bool found; entry = kvm_find_cpuid_entry(vcpu, function, index); @@ -1015,18 +1015,17 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, */ if (!entry && check_limit && !guest_cpuid_is_amd(vcpu) && !cpuid_function_in_range(vcpu, function)) { - max = kvm_find_cpuid_entry(vcpu, 0, 0); - if (max) { - function = max->eax; - entry = kvm_find_cpuid_entry(vcpu, function, index); - } + entry = kvm_find_cpuid_entry(vcpu, 0, 0); + if (entry) + entry = kvm_find_cpuid_entry(vcpu, entry->eax, index); } if (entry) { *eax = entry->eax; *ebx = entry->ebx; *ecx = entry->ecx; *edx = entry->edx; - if (function == 7 && index == 0) { + + if (entry->function == 7 && index == 0) { u64 data; if (!__kvm_get_msr(vcpu, MSR_IA32_TSX_CTRL, &data, true) && (data & TSX_CTRL_CPUID_CLEAR)) -- 2.24.1
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