On 2/29/2024 2:36 PM, Xiaoyao Li wrote:
tdx_cpuid_lookup[].tdx_fixed0/1 is QEMU maintained data which reflects TDX restrictions regrading what bits are fixed by TDX module. It's retrieved from TDX spec and static. However, TDX may evolve and change some fixed fields to configurable in the future. Update tdx_cpuid.lookup[].tdx_fixed0/1 fields by removing the bits that reported from TDX module as configurable. This can adapt with the updated TDX (module) automatically.
Can the fixed fields evolves to other type, i.e., native?
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx> --- target/i386/kvm/tdx.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c index 239170142e4f..424c0f3c0fbb 100644 --- a/target/i386/kvm/tdx.c +++ b/target/i386/kvm/tdx.c @@ -377,6 +377,38 @@ static int get_tdx_capabilities(Error **errp) return 0; }+static void update_tdx_cpuid_lookup_by_tdx_caps(void)+{ + KvmTdxCpuidLookup *entry; + FeatureWordInfo *fi; + uint32_t config; + FeatureWord w; + + for (w = 0; w < FEATURE_WORDS; w++) { + fi = &feature_word_info[w]; + entry = &tdx_cpuid_lookup[w]; + + if (fi->type != CPUID_FEATURE_WORD) { + continue; + } + + config = tdx_cap_cpuid_config(fi->cpuid.eax, + fi->cpuid.needs_ecx ? fi->cpuid.ecx : ~0u,
So the check "cpuid_c->sub_leaf == 0xffffffff" in tdx_cap_cpuid_config() is unnecessary?
Thanks Zhenzhong
+ fi->cpuid.reg); + + if (!config) { + continue; + } + + /* + * Remove the configurable bits from tdx_fixed0/1 in case QEMU + * maintained fixed0/1 values is outdated to TDX module. + */ + entry->tdx_fixed0 &= ~config; + entry->tdx_fixed1 &= ~config; + } +} + static int tdx_kvm_init(ConfidentialGuestSupport *cgs, Error **errp) { MachineState *ms = MACHINE(qdev_get_machine()); @@ -392,6 +424,8 @@ static int tdx_kvm_init(ConfidentialGuestSupport *cgs, Error **errp) } }+ update_tdx_cpuid_lookup_by_tdx_caps();+ tdx_guest = tdx; return 0; }
