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 <farrah.chen@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20251211060801.3600039-11-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index e9ef8b992fda90850aaea09163c144dd8b72500a..8c00a3ad4df7f0510d1a6a8c30be148433a853c1 100644 (file)
--- 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;