[Xen-devel] [PATCH v3] x86/HVM: add padding to struct hvm_hw_cpu

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

So that the size of the structure is the same on 32 and 64bit.

Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
This should fix the issues seen on OSSTest when using a 32bit toolstack on
a 64bit hypervisor to create a Windows 7 HVM guest.
---
Chnges since v2:
 - Fall back to adding a padding field and properly checking for it to be 0.

Changes since v1:
 - Instead of adding padding, change the flags field to be a uint64_t.
---
 xen/arch/x86/hvm/hvm.c                 | 3 +++
 xen/include/public/arch-x86/hvm/save.h | 1 +
 2 files changed, 4 insertions(+)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index a99edc2..cc5d14b 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -1990,6 +1990,9 @@ static int hvm_load_cpu_ctxt(struct domain *d, 
hvm_domain_context_t *h)
     if ( hvm_load_entry_zeroextend(CPU, h, &ctxt) != 0 )
         return -EINVAL;
 
+    if ( ctxt.pad0 != 0 )
+        return -EINVAL;
+
     /* Sanity check some control registers. */
     if ( (ctxt.cr0 & HVM_CR0_GUEST_RESERVED_BITS) ||
          !(ctxt.cr0 & X86_CR0_ET) ||
diff --git a/xen/include/public/arch-x86/hvm/save.h 
b/xen/include/public/arch-x86/hvm/save.h
index b6b1bf8..6862720 100644
--- a/xen/include/public/arch-x86/hvm/save.h
+++ b/xen/include/public/arch-x86/hvm/save.h
@@ -163,6 +163,7 @@ struct hvm_hw_cpu {
 #define _XEN_X86_FPU_INITIALISED        0
 #define XEN_X86_FPU_INITIALISED         (1U<<_XEN_X86_FPU_INITIALISED)
     uint32_t flags;
+    uint32_t pad0;
 };
 
 struct hvm_hw_cpu_compat {
-- 
1.9.5 (Apple Git-50.3)


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