From: Zhao Liu Date: Thu, 11 Dec 2025 06:07:49 +0000 (+0800) Subject: i386/cpu: Add missing migratable xsave features X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=54fed32ec1a02b9001d72377202702bce0bc8ac5;p=thirdparty%2Fqemu.git i386/cpu: Add missing migratable xsave features Xtile-cfg & xtile-data are both user xstates. Their xstates are cached in X86CPUState, and there's a related vmsd "vmstate_amx_xtile", so that it's safe to mark them as migratable. Arch lbr xstate is a supervisor xstate, and it is save & load by saving & loading related arch lbr MSRs, which are cached in X86CPUState, and there's a related vmsd "vmstate_arch_lbr". So it should be migratable. PT is still unmigratable since KVM disabled it and there's no vmsd and no other emulation/simulation support. Note, though the migratable_flags get fixed, x86_cpu_enable_xsave_components() still overrides supported xstates bitmaps regardless the masking of migratable_flags. This is another issue, and would be fixed in follow-up refactoring. Tested-by: Farrah Chen Signed-off-by: Zhao Liu Link: https://lore.kernel.org/r/20251211060801.3600039-11-zhao1.liu@intel.com Signed-off-by: Paolo Bonzini --- diff --git a/target/i386/cpu.c b/target/i386/cpu.c index e9ef8b992f..8c00a3ad4d 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -1484,6 +1484,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = { .ecx = 1, .reg = R_ECX, }, + .migratable_flags = XSTATE_ARCH_LBR_MASK, }, [FEAT_XSAVE_XSS_HI] = { .type = CPUID_FEATURE_WORD, @@ -1522,7 +1523,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = { .migratable_flags = XSTATE_FP_MASK | XSTATE_SSE_MASK | XSTATE_YMM_MASK | XSTATE_BNDREGS_MASK | XSTATE_BNDCSR_MASK | XSTATE_OPMASK_MASK | XSTATE_ZMM_Hi256_MASK | XSTATE_Hi16_ZMM_MASK | - XSTATE_PKRU_MASK, + XSTATE_PKRU_MASK | XSTATE_XTILE_CFG_MASK | XSTATE_XTILE_DATA_MASK, }, [FEAT_XSAVE_XCR0_HI] = { .type = CPUID_FEATURE_WORD, @@ -2154,8 +2155,13 @@ static uint64_t x86_cpu_get_migratable_flags(X86CPU *cpu, FeatureWord w) for (i = 0; i < 64; i++) { uint64_t f = 1ULL << i; - /* If the feature name is known, it is implicitly considered migratable, - * unless it is explicitly set in unmigratable_flags */ + /* + * If the feature name is known, it is implicitly considered migratable, + * unless it is explicitly set in unmigratable_flags. + * + * TODO: Make the behavior of x86_cpu_enable_xsave_components() align + * with migratable_flags masking. + */ if ((wi->migratable_flags & f) || (wi->feat_names[i] && !(wi->unmigratable_flags & f))) { r |= f;