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| author | Jan Beulich <jbeulich@suse.com> | 2013-07-02 08:41:28 +0200 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2013-07-02 08:41:28 +0200 |
| commit | f9755488bf17c056111d1e442be394cfb63d7788 (patch) | |
| tree | 224e860b016512cac04f1d67503ad30ea1f391a2 /xen/arch/x86/domain.c | |
| parent | 7b62e6bd2fcc862360c741cf64d2cbce7825402b (diff) | |
| download | xen-f9755488bf17c056111d1e442be394cfb63d7788.tar.gz xen-f9755488bf17c056111d1e442be394cfb63d7788.tar.bz2 xen-f9755488bf17c056111d1e442be394cfb63d7788.zip | |
x86/xsave: adjust state management
The initial state for a vCPU is using default values, so there's no
need to force the XRSTOR to read the state from memory. This saves a
couple of thousand restores from memory just during boot of Linux on
my Sandy Bridge system (I didn't try to make further measurements).
The above requires that arch_set_info_guest() updates the state flags
in the save area when valid floating point state got passed in, but
that would really have been needed even before in case XSAVE{,OPT}
decided to clear one or both of the FP and SSE bits.
Furthermore, hvm_vcpu_reset_state() shouldn't just clear out the FPU/
SSE area, but needs to re-initialized MXCSR and FCW.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
Diffstat (limited to 'xen/arch/x86/domain.c')
| -rw-r--r-- | xen/arch/x86/domain.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c index 52c9040f59..874742c3b1 100644 --- a/xen/arch/x86/domain.c +++ b/xen/arch/x86/domain.c @@ -712,7 +712,11 @@ int arch_set_info_guest( v->arch.vgc_flags = flags; if ( flags & VGCF_I387_VALID ) + { memcpy(v->arch.fpu_ctxt, &c.nat->fpu_ctxt, sizeof(c.nat->fpu_ctxt)); + if ( v->arch.xsave_area ) + v->arch.xsave_area->xsave_hdr.xstate_bv = XSTATE_FP_SSE; + } if ( !compat ) { |