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i386/tdx: Don't mask off CPUID_EXT_PDCM

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It gets below warning when booting TDX VMs:

  warning: TDX forcibly sets the feature: CPUID[eax=01h].ECX.pdcm [bit 15]

Because CPUID_EXT_PDCM is fixed1 for TDX, and MSR_IA32_PERF_CAPABILITIES is
supported for TDX guest unconditioanlly.

Don't mask off CPUID_EXT_PDCM for TDX.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250625035710.2770679-1-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Xiaoyao Li 2025-06-25 11:57:10 +08:00 • committed by Paolo Bonzini
parent 50fd57418c
commit 7ff24fb657
1 changed files with 3 additions and 1 deletions
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4
target/i386/cpu.c
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@ -28,6 +28,7 @@
#include "system/hvf.h"
#include "hvf/hvf-i386.h"
#include "kvm/kvm_i386.h"
#include "kvm/tdx.h"
#include "sev.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
@ -8336,7 +8337,8 @@ void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
}
}
if (!cpu->enable_pmu) {
/* PDCM is fixed1 bit for TDX */
if (!cpu->enable_pmu && !is_tdx_vm()) {
mark_unavailable_features(cpu, FEAT_1_ECX,
env->user_features[FEAT_1_ECX] & CPUID_EXT_PDCM,
"This feature is not available due to PMU being disabled");