[Xen-changelog] [xen master] x86/xsaves: get_xsave_addr, check xsave header and support uncompressed format

[patchbot@xxxxxxx]

commit 2a4b84706e5e67be4e3e3a023d4a0a7169b19b45
Author:     Huaitong Han <huaitong.han@xxxxxxxxx>
AuthorDate: Mon Dec 21 13:37:17 2015 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Dec 21 13:37:17 2015 +0100

    x86/xsaves: get_xsave_addr, check xsave header and support uncompressed 
format
    
    The check needs to be against the xsave header in the area, rather than 
Xen's
    maximum xfeature_mask. A guest might easily have a smaller xcr0 than the
    maximum Xen is willing to allow, causing the pointer below to be bogus.
    
    The get_xsave_addr() is modified to support uncompressed xstate areas.
    
    Signed-off-by: Huaitong Han <huaitong.han@xxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/xstate.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/xstate.c b/xen/arch/x86/xstate.c
index b65da38..4e87ab3 100644
--- a/xen/arch/x86/xstate.c
+++ b/xen/arch/x86/xstate.c
@@ -146,12 +146,15 @@ static void __init setup_xstate_comp(void)
     }
 }
 
-static void *get_xsave_addr(void *xsave, unsigned int xfeature_idx)
+static void *get_xsave_addr(struct xsave_struct *xsave,
+        unsigned int xfeature_idx)
 {
-    if ( !((1ul << xfeature_idx) & xfeature_mask) )
+    if ( !((1ul << xfeature_idx) & xsave->xsave_hdr.xstate_bv) )
         return NULL;
 
-    return xsave + xstate_comp_offsets[xfeature_idx];
+    return (void *)xsave + (xsave_area_compressed(xsave)
+            ? xstate_comp_offsets
+            : xstate_offsets)[xfeature_idx];
 }
 
 void expand_xsave_states(struct vcpu *v, void *dest, unsigned int size)
--
generated by git-patchbot for /home/xen/git/xen.git#master

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