On 05/28/2015 01:05 AM, Paolo Bonzini wrote:
This is now very simple to do. The only interesting part is a simple
trick to find the right memslot in gfn_to_rmap, retrieving the address
space from the spte role word. The same trick is used in the auditing
code.
The comment on top of union kvm_mmu_page_role has been stale forever,
Fortunately, we have documented these fields in mmu.txt, please do it for
'smm' as well. :)
so remove it. Speaking of stale code, remove pad_for_nice_hex_output
too: it was splitting the "access" bitfield across two bytes and thus
had effectively turned into pad_for_ugly_hex_output.
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
v1->v2: new
arch/x86/include/asm/kvm_host.h | 26 +++++++++++++++-----------
arch/x86/kvm/mmu.c | 15 ++++++++++++---
arch/x86/kvm/mmu_audit.c | 10 +++++++---
arch/x86/kvm/x86.c | 2 ++
4 files changed, 36 insertions(+), 17 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 5a5e13af6e03..47006683f2fe 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -184,23 +184,12 @@ struct kvm_mmu_memory_cache {
void *objects[KVM_NR_MEM_OBJS];
};
-/*
- * kvm_mmu_page_role, below, is defined as:
- *
- * bits 0:3 - total guest paging levels (2-4, or zero for real mode)
- * bits 4:7 - page table level for this shadow (1-4)
- * bits 8:9 - page table quadrant for 2-level guests
- * bit 16 - direct mapping of virtual to physical mapping at gfn
- * used for real mode and two-dimensional paging
- * bits 17:19 - common access permissions for all ptes in this shadow page
- */
union kvm_mmu_page_role {
unsigned word;
struct {
unsigned level:4;
unsigned cr4_pae:1;
unsigned quadrant:2;
- unsigned pad_for_nice_hex_output:6;
unsigned direct:1;
unsigned access:3;
unsigned invalid:1;
@@ -208,6 +197,15 @@ union kvm_mmu_page_role {
unsigned cr0_wp:1;
unsigned smep_andnot_wp:1;
unsigned smap_andnot_wp:1;
+ unsigned :8;
+
+ /*
+ * This is left at the top of the word so that
+ * kvm_memslots_for_spte_role can extract it with a
+ * simple shift. While there is room, give it a whole
+ * byte so it is also faster to load it from memory.
+ */
+ unsigned smm:8;
I suspect if we really need this trick, smm is not the hottest filed in this
struct anyway.
Otherwise looks good to me:
Reviewed-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
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