diff options
| author | Babu Moger <babu.moger@amd.com> | 2020-04-17 16:55:13 -0500 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-06-10 12:09:42 -0400 |
| commit | cac9edfc4dad2a7d2ad7e23e0de4edc41801e346 (patch) | |
| tree | b51f9f2ec42d2994c2797de3f7fdf24d95bbb732 /target/i386 | |
| parent | 4dd8a7064b8a6527f99a62be11a5124e65cae270 (diff) | |
target/i386: Fix the CPUID leaf CPUID_Fn80000008
CPUID leaf CPUID_Fn80000008_ECX provides information about the
number of threads supported by the processor. It was found that
the field ApicIdSize(bits 15-12) was not set correctly.
ApicIdSize is defined as the number of bits required to represent
all the ApicId values within a package.
Valid Values: Value Description
3h-0h Reserved.
4h up to 16 threads.
5h up to 32 threads.
6h up to 64 threads.
7h up to 128 threads.
Fh-8h Reserved.
Fix the bit appropriately.
This came up during following thread.
https://lore.kernel.org/qemu-devel/158643709116.17430.15995069125716778943.malonedeb@wampee.canonical.com/#t
Refer the Processor Programming Reference (PPR) for AMD Family 17h
Model 01h, Revision B1 Processors. The documentation is available
from the bugzilla Link below.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Reported-by: Philipp Eppelt <1871842@bugs.launchpad.net>
Signed-off-by: Babu Moger <babu.moger@amd.com>
Message-Id: <20200417215345.64800.73351.stgit@localhost.localdomain>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'target/i386')
| -rw-r--r-- | target/i386/cpu.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index ba05da3f2e..25a8f6b1ad 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -5837,11 +5837,20 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, *eax = cpu->phys_bits; } *ebx = env->features[FEAT_8000_0008_EBX]; - *ecx = 0; - *edx = 0; if (cs->nr_cores * cs->nr_threads > 1) { - *ecx |= (cs->nr_cores * cs->nr_threads) - 1; + /* + * Bits 15:12 is "The number of bits in the initial + * Core::X86::Apic::ApicId[ApicId] value that indicate + * thread ID within a package". This is already stored at + * CPUX86State::pkg_offset. + * Bits 7:0 is "The number of threads in the package is NC+1" + */ + *ecx = (env->pkg_offset << 12) | + ((cs->nr_cores * cs->nr_threads) - 1); + } else { + *ecx = 0; } + *edx = 0; break; case 0x8000000A: if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_SVM) { |