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| author | Jan Beulich <jbeulich@suse.com> | 2013-08-05 18:42:37 +0200 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2013-08-05 18:42:37 +0200 |
| commit | c58d9f2f4844c2ce8859a8d0f26a54cd058eb51f (patch) | |
| tree | 5077dcef946d26596d2264050263e55018272435 /xen | |
| parent | b0e55bd49725c7c0183eb18670997b9e5930adac (diff) | |
| download | xen-c58d9f2f4844c2ce8859a8d0f26a54cd058eb51f.tar.gz xen-c58d9f2f4844c2ce8859a8d0f26a54cd058eb51f.tar.bz2 xen-c58d9f2f4844c2ce8859a8d0f26a54cd058eb51f.zip | |
x86: refine FPU selector handling code for XSAVEOPT
Some extra tweaks are necessary to deal with the situation of XSAVEOPT
not writing the FPU portion of the save image (due to it detecting that
the register state did not get modified since the last XRSTOR).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Ben Guthro <ben.guthro@gmail.com>
Acked-by: Keir Fraser <keir@xen.org>
Diffstat (limited to 'xen')
| -rw-r--r-- | xen/arch/x86/xstate.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/xen/arch/x86/xstate.c b/xen/arch/x86/xstate.c index 608accfe48..2c007062ab 100644 --- a/xen/arch/x86/xstate.c +++ b/xen/arch/x86/xstate.c @@ -71,10 +71,28 @@ void xsave(struct vcpu *v, uint64_t mask) if ( word_size <= 0 || !is_pv_32bit_vcpu(v) ) { + typeof(ptr->fpu_sse.fip.sel) fcs = ptr->fpu_sse.fip.sel; + typeof(ptr->fpu_sse.fdp.sel) fds = ptr->fpu_sse.fdp.sel; + if ( cpu_has_xsaveopt ) + { + /* + * xsaveopt may not write the FPU portion even when the respective + * mask bit is set. For the check further down to work we hence + * need to put the save image back into the state that it was in + * right after the previous xsaveopt. + */ + if ( word_size > 0 && + (ptr->fpu_sse.x[FPU_WORD_SIZE_OFFSET] == 4 || + ptr->fpu_sse.x[FPU_WORD_SIZE_OFFSET] == 2) ) + { + ptr->fpu_sse.fip.sel = 0; + ptr->fpu_sse.fdp.sel = 0; + } asm volatile ( ".byte 0x48,0x0f,0xae,0x37" : "=m" (*ptr) : "a" (lmask), "d" (hmask), "D" (ptr) ); + } else asm volatile ( ".byte 0x48,0x0f,0xae,0x27" : "=m" (*ptr) @@ -87,7 +105,14 @@ void xsave(struct vcpu *v, uint64_t mask) */ (!(ptr->fpu_sse.fsw & 0x0080) && boot_cpu_data.x86_vendor == X86_VENDOR_AMD) ) + { + if ( cpu_has_xsaveopt && word_size > 0 ) + { + ptr->fpu_sse.fip.sel = fcs; + ptr->fpu_sse.fdp.sel = fds; + } return; + } if ( word_size > 0 && !((ptr->fpu_sse.fip.addr | ptr->fpu_sse.fdp.addr) >> 32) ) |