On 24/11/2022 7:33 pm, Thomas Huth wrote:
On 02/11/2022 23.50, Sean Christopherson wrote:From: Like Xu <likexu@xxxxxxxxxxx> Specifying an unsupported PMC encoding will cause a #GP(0). There are multiple reasons RDPMC can #GP, the one that is being relied on to guarantee #GP is specifically that the PMC is invalid. The most extensible solution is to provide a safe variant. Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Like Xu <likexu@xxxxxxxxxxx> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> --- lib/x86/processor.h | 21 ++++++++++++++++++--- x86/pmu.c | 10 ++++++++++ 2 files changed, 28 insertions(+), 3 deletions(-) diff --git a/lib/x86/processor.h b/lib/x86/processor.h index f85abe36..ba14c7a0 100644 --- a/lib/x86/processor.h +++ b/lib/x86/processor.h @@ -438,11 +438,26 @@ static inline int wrmsr_safe(u32 index, u64 val) return exception_vector(); } +static inline int rdpmc_safe(u32 index, uint64_t *val) +{ + uint32_t a, d; + + asm volatile (ASM_TRY("1f") + "rdpmc\n\t" + "1:" + : "=a"(a), "=d"(d) : "c"(index) : "memory"); + *val = (uint64_t)a | ((uint64_t)d << 32); + return exception_vector(); +} + static inline uint64_t rdpmc(uint32_t index) { - uint32_t a, d; - asm volatile ("rdpmc" : "=a"(a), "=d"(d) : "c"(index)); - return a | ((uint64_t)d << 32); + uint64_t val; + int vector = rdpmc_safe(index, &val); + + assert_msg(!vector, "Unexpected %s on RDPMC(%d)", + exception_mnemonic(vector), index); + return val; }Seems like this is causing the CI to fail: https://gitlab.com/kvm-unit-tests/kvm-unit-tests/-/jobs/3339274319#L1260
I just now noticed that KUT can be used to validate TCG or HVF accel on macOS. I assume the functionality of the PMU counter on TCG seems to be a blank slate.
I guess you have to use PRId32 here? Could you please send a patch?
Sure, let me try it on the macOS.
Thanks, Thomas
