| Message ID | 20200302195736.24777-1-sean.j.christopherson@intel.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | KVM: x86: CPUID emulation and tracing fixes | expand |
On 02/03/20 20:57, Sean Christopherson wrote: > Two fixes related to out-of-range CPUID emulation and related cleanup on > top. > > I have a unit test and also manually verified a few interesting cases. > I'm not planning on posting the unit test at this time because I haven't > figured out how to avoid false positives, e.g. if a random in-bounds > leaf just happens to match the output of a max basic leaf. It might be > doable by hardcoding the cpu model? It would be best suited for selftests rather than kvm-unit-tests. But I don't really see the benefit of anything more than just diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index b1c469446b07..c1abf5de4461 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -1001,6 +1001,7 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx, bool check_limit) { u32 function = *eax, index = *ecx; + u32 orig_function = function; struct kvm_cpuid_entry2 *entry; struct kvm_cpuid_entry2 *max; bool found; @@ -1049,7 +1050,7 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, } } } - trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx, found); + trace_kvm_cpuid(orig_function, *eax, *ebx, *ecx, *edx, found); return found; } EXPORT_SYMBOL_GPL(kvm_cpuid);
On Tue, Mar 03, 2020 at 09:48:44AM +0100, Paolo Bonzini wrote: > On 02/03/20 20:57, Sean Christopherson wrote: > > Two fixes related to out-of-range CPUID emulation and related cleanup on > > top. > > > > I have a unit test and also manually verified a few interesting cases. > > I'm not planning on posting the unit test at this time because I haven't > > figured out how to avoid false positives, e.g. if a random in-bounds > > leaf just happens to match the output of a max basic leaf. It might be > > doable by hardcoding the cpu model? > > It would be best suited for selftests rather than kvm-unit-tests. But I > don't really see the benefit of anything more than just Gotta save those stack bytes? I got a bit confused by the "max" variable; I thought it would hold the max basic leaf, not CPUID.0x0. Removing it seemed easier than trying to come up with a better name :-) > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index b1c469446b07..c1abf5de4461 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -1001,6 +1001,7 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, > u32 *ecx, u32 *edx, bool check_limit) > { > u32 function = *eax, index = *ecx; > + u32 orig_function = function; > struct kvm_cpuid_entry2 *entry; > struct kvm_cpuid_entry2 *max; > bool found; > @@ -1049,7 +1050,7 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, > } > } > } > - trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx, found); > + trace_kvm_cpuid(orig_function, *eax, *ebx, *ecx, *edx, found); > return found; > } > EXPORT_SYMBOL_GPL(kvm_cpuid); >
Two fixes related to out-of-range CPUID emulation and related cleanup on top. I have a unit test and also manually verified a few interesting cases. I'm not planning on posting the unit test at this time because I haven't figured out how to avoid false positives, e.g. if a random in-bounds leaf just happens to match the output of a max basic leaf. It might be doable by hardcoding the cpu model? Sean Christopherson (6): KVM: x86: Fix tracing of CPUID.function when function is out-of-range KVM: x86: Fix CPUID range check for Centaur and Hypervisor ranges KVM: x86: Add dedicated emulator helper for grabbing CPUID.maxphyaddr KVM: x86: Drop return value from kvm_cpuid() KVM: x86: Rename "found" variable in kvm_cpuid() to "exact_entry_exists" KVM: x86: Add requested index to the CPUID tracepoint arch/x86/include/asm/kvm_emulate.h | 3 ++- arch/x86/kvm/cpuid.c | 26 ++++++++++++-------------- arch/x86/kvm/cpuid.h | 2 +- arch/x86/kvm/emulate.c | 10 +--------- arch/x86/kvm/trace.h | 13 ++++++++----- arch/x86/kvm/x86.c | 10 ++++++++-- 6 files changed, 32 insertions(+), 32 deletions(-)