[libvirt] [PATCH v2 2/3] i386/kvm: Blacklist TSX on known broken hosts

Some Intel CPUs are known to have a broken TSX implementation. A microcode update from Intel disabled TSX on those CPUs, but GET_SUPPORTED_CPUID might be reporting it as supported if the hosts were not updated yet. Manually fixup the GET_SUPPORTED_CPUID data to ensure we will never enable TSX when running on those hosts. Reference: * glibc commit 2702856bf45c82cf8e69f2064f5aa15c0ceb6359: https://sourceware.org/git/?p=glibc.git;a=commit;h=2702856bf45c82cf8e69f2... Signed-off-by: Eduardo Habkost <ehabkost(a)redhat.com&gt; --- target/i386/kvm.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/target/i386/kvm.c b/target/i386/kvm.c index 27fd0505df..2694f35e74 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -273,6 +273,19 @@ static int get_para_features(KVMState *s) return features; } +static bool host_tsx_blacklisted(void) +{ + int family, model, stepping;\ + char vendor[CPUID_VENDOR_SZ + 1]; + + host_vendor_fms(vendor, &family, &model, &stepping); + + /* Check if we are running on a Haswell host known to have broken TSX */ + return !strcmp(vendor, CPUID_VENDOR_INTEL) && + (family == 6) && + ((model == 63 && stepping < 4) || + model == 60 || model == 69 || model == 70); +} /* Returns the value for a specific register on the cpuid entry */ @@ -356,6 +369,10 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function, } } else if (function == 6 && reg == R_EAX) { ret |= CPUID_6_EAX_ARAT; /* safe to allow because of emulated APIC */ + } else if (function == 7 && index == 0 && reg == R_EBX) { + if (host_tsx_blacklisted()) { + ret &= ~(CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_HLE); + } } else if (function == 0x80000001 && reg == R_EDX) { /* On Intel, kvm returns cpuid according to the Intel spec, * so add missing bits according to the AMD spec: -- 2.11.0.259.g40922b1