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target/i386: suppress CPUID leaves not defined by the CPU vendor

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Currently all built-in CPUs report cache information via CPUID leaves 2
and 4, but these have never been defined for AMD. In the case of
SEV-SNP this can cause issues with CPUID enforcement. Address this by
allowing CPU types to suppress these via a new "x-vendor-cpuid-only"
CPU property, which is true by default, but switched off for older
machine types to maintain compatibility.

Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: zhenwei pi <pizhenwei@bytedance.com>
Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Message-Id: <20210708003623.18665-1-michael.roth@amd.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
This commit is contained in:
Michael Roth 2021-07-07 19:36:23 -05:00 committed by Eduardo Habkost
parent cce087f628
commit a7a0da844d
3 changed files with 10 additions and 0 deletions
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1
hw/i386/pc.c
View file

@ -98,6 +98,7 @@ GlobalProperty pc_compat_6_0[] = {
{ "qemu64" "-" TYPE_X86_CPU, "family", "6" },
{ "qemu64" "-" TYPE_X86_CPU, "model", "6" },
{ "qemu64" "-" TYPE_X86_CPU, "stepping", "3" },
{ TYPE_X86_CPU, "x-vendor-cpuid-only", "off" },
};
const size_t pc_compat_6_0_len = G_N_ELEMENTS(pc_compat_6_0);

6
target/i386/cpu.c
View file

@ -5155,6 +5155,9 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
if (cpu->cache_info_passthrough) {
host_cpuid(index, 0, eax, ebx, ecx, edx);
break;
} else if (cpu->vendor_cpuid_only && IS_AMD_CPU(env)) {
*eax = *ebx = *ecx = *edx = 0;
break;
}
*eax = 1; /* Number of CPUID[EAX=2] calls required */
*ebx = 0;
@ -5176,6 +5179,8 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
if ((*eax & 31) && cs->nr_cores > 1) {
*eax |= (cs->nr_cores - 1) << 26;
}
} else if (cpu->vendor_cpuid_only && IS_AMD_CPU(env)) {
*eax = *ebx = *ecx = *edx = 0;
} else {
*eax = 0;
switch (count) {
@ -6651,6 +6656,7 @@ static Property x86_cpu_properties[] = {
DEFINE_PROP_BOOL("full-cpuid-auto-level", X86CPU, full_cpuid_auto_level, true),
DEFINE_PROP_STRING("hv-vendor-id", X86CPU, hyperv_vendor),
DEFINE_PROP_BOOL("cpuid-0xb", X86CPU, enable_cpuid_0xb, true),
DEFINE_PROP_BOOL("x-vendor-cpuid-only", X86CPU, vendor_cpuid_only, true),
DEFINE_PROP_BOOL("lmce", X86CPU, enable_lmce, false),
DEFINE_PROP_BOOL("l3-cache", X86CPU, enable_l3_cache, true),
DEFINE_PROP_BOOL("kvm-no-smi-migration", X86CPU, kvm_no_smi_migration,

3
target/i386/cpu.h
View file

@ -1748,6 +1748,9 @@ struct X86CPU {
/* Enable auto level-increase for all CPUID leaves */
bool full_cpuid_auto_level;
/* Only advertise CPUID leaves defined by the vendor */
bool vendor_cpuid_only;
/* Enable auto level-increase for Intel Processor Trace leave */
bool intel_pt_auto_level;