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Re: [Qemu-devel] [PATCH] target-i386: Report known CPUID[EAX=0xD, ECX=0]
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] [PATCH] target-i386: Report known CPUID[EAX=0xD, ECX=0]:EAX bits as migratable |
Date: |
Thu, 29 Sep 2016 15:40:39 -0300 |
User-agent: |
Mutt/1.7.0 (2016-08-17) |
(CCing Richard, sorry I forgot to CC you)
Ping? Any objection to this fix?
On Wed, Sep 28, 2016 at 01:33:15PM -0300, Eduardo Habkost wrote:
> A regression was introduced by commit 96193c22a "target-i386:
> Move xsave component mask to features array": all
> CPUID[EAX=0xD,ECX=0]:EAX bits were being reported as unmigratable
> because they don't have feature names defined. This broke
> "-cpu host" because it enables only migratable features by
> default.
>
> This adds a new field to FeatureWordInfo: migratable_flags, which
> will make those features be reported as migratable even if they
> don't have a property name defined.
>
> Reported-by: Wanpeng Li <address@hidden>
> Cc: Paolo Bonzini <address@hidden>
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
> target-i386/cpu.c | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 333309b..0807e92 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -258,6 +258,7 @@ typedef struct FeatureWordInfo {
> int cpuid_reg; /* output register (R_* constant) */
> uint32_t tcg_features; /* Feature flags supported by TCG */
> uint32_t unmigratable_flags; /* Feature flags known to be unmigratable */
> + uint32_t migratable_flags; /* Feature flags known to be migratable */
> } FeatureWordInfo;
>
> static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
> @@ -494,6 +495,10 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS]
> = {
> .cpuid_needs_ecx = true, .cpuid_ecx = 0,
> .cpuid_reg = R_EAX,
> .tcg_features = ~0U,
> + .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,
> },
> [FEAT_XSAVE_COMP_HI] = {
> .cpuid_eax = 0xD,
> @@ -600,15 +605,13 @@ static uint32_t
> x86_cpu_get_migratable_flags(FeatureWord w)
>
> for (i = 0; i < 32; i++) {
> uint32_t f = 1U << i;
> - /* If the feature name is unknown, it is not supported by QEMU yet */
> - if (!wi->feat_names[i]) {
> - continue;
> - }
> - /* Skip features known to QEMU, but explicitly marked as
> unmigratable */
> - if (wi->unmigratable_flags & f) {
> - continue;
> +
> + /* If the feature name is known, it is implicitly considered
> migratable,
> + * unless it is explicitly set in unmigratable_flags */
> + if ((wi->migratable_flags & f) ||
> + (wi->feat_names[i] && !(wi->unmigratable_flags & f))) {
> + r |= f;
> }
> - r |= f;
> }
> return r;
> }
> --
> 2.7.4
>
>
--
Eduardo