On Tue, Apr 01, 2025 at 09:01:54AM -0400, Xiaoyao Li wrote:
> Date: Tue, 1 Apr 2025 09:01:54 -0400
> From: Xiaoyao Li <xiaoyao...@intel.com>
> Subject: [PATCH v8 44/55] i386/tdx: Implement adjust_cpuid_features() for
> TDX
> X-Mailer: git-send-email 2.34.1
>
> Maintain a TDX specific supported CPUID set, and use it to mask the
> common supported CPUID value of KVM. It can avoid newly added supported
> features (reported via KVM_GET_SUPPORTED_CPUID) for common VMs being
> falsely reported as supported for TDX.
>
> As the first step, initialize the TDX supported CPUID set with all the
> configurable CPUID bits. It's not complete because there are other CPUID
> bits are supported for TDX but not reported as directly configurable.
> E.g. the XFAM related bits, attribute related bits and fixed-1 bits.
> They will be handled in the future.
>
> Also, what matters are the CPUID bits related to QEMU's feature word.
> Only mask the CPUID leafs which are feature word leaf.
>
> Signed-off-by: Xiaoyao Li <xiaoyao...@intel.com>
> ---
> target/i386/cpu.c | 18 ++++++++++++++++++
> target/i386/cpu.h | 1 +
> target/i386/kvm/kvm.c | 2 +-
> target/i386/kvm/kvm_i386.h | 1 +
> target/i386/kvm/tdx.c | 34 ++++++++++++++++++++++++++++++++++
> 5 files changed, 55 insertions(+), 1 deletion(-)
Reviewed-by: Zhao Liu <zhao1....@intel.com>
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index f219961b62cd..4061d38d3fbe 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -1655,6 +1655,24 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
> },
> };
>
> +bool is_feature_word_cpuid(uint32_t feature, uint32_t index, int reg)
> +{
> + FeatureWordInfo *wi;
> + FeatureWord w;
> +
> + for (w = 0; w < FEATURE_WORDS; w++)
> + {
(style nit?) "{" should be at the end of the previous line?
> + wi = &feature_word_info[w];
> + if (wi->type == CPUID_FEATURE_WORD && wi->cpuid.eax == feature &&
> + (!wi->cpuid.needs_ecx || wi->cpuid.ecx == index) &&
> + wi->cpuid.reg == reg)
> + {
ditto.
> + return true;
> + }
> + }
> + return false;
> +}
> +
