[PATCH v3 05/12] x86/hvm: Map/unmap xsave area in hvmemul_{get,put}_fpu()

[Alejandro Vallejo <alejandro.vallejo@cloud.com>]

No functional change.

Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
---
v2->v3:
  * style: Capitalized first letter of the fastpath comment
  * Added A-by

v1->v2:
  * Added comments highlighting fastpath for current
---
 xen/arch/x86/hvm/emulate.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index a1935a174830..d5011612aff0 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -2371,7 +2371,9 @@ static int cf_check hvmemul_get_fpu(
         alternative_vcall(hvm_funcs.fpu_dirty_intercept);
     else if ( type == X86EMUL_FPU_fpu )
     {
-        const fpusse_t *fpu_ctxt = &curr->arch.xsave_area->fpu_sse;
+        /* Has a fastpath for `current`, so there's no actual map */
+        const struct xsave_struct *xsave_area = VCPU_MAP_XSAVE_AREA(curr);
+        const fpusse_t *fpu_ctxt = &xsave_area->fpu_sse;
 
         /*
          * Latch current register state so that we can back out changes
@@ -2397,6 +2399,8 @@ static int cf_check hvmemul_get_fpu(
             else
                 ASSERT(fcw == fpu_ctxt->fcw);
         }
+
+        VCPU_UNMAP_XSAVE_AREA(curr, xsave_area);
     }
 
     return X86EMUL_OKAY;
@@ -2411,7 +2415,9 @@ static void cf_check hvmemul_put_fpu(
 
     if ( aux )
     {
-        fpusse_t *fpu_ctxt = &curr->arch.xsave_area->fpu_sse;
+        /* Has a fastpath for `current`, so there's no actual map */
+        struct xsave_struct *xsave_area = VCPU_MAP_XSAVE_AREA(curr);
+        fpusse_t *fpu_ctxt = &xsave_area->fpu_sse;
         bool dval = aux->dval;
         int mode = hvm_guest_x86_mode(curr);
 
@@ -2467,6 +2473,8 @@ static void cf_check hvmemul_put_fpu(
 
         fpu_ctxt->fop = aux->op;
 
+        VCPU_UNMAP_XSAVE_AREA(curr, xsave_area);
+
         /* Re-use backout code below. */
         backout = X86EMUL_FPU_fpu;
     }
-- 
2.47.1