On 09/10/2009 07:38 PM, Izik Eidus wrote:
this flag notify that the host physical page we are pointing to from
the spte is write protected, and therefore we cant change its access
to be write unless we run get_user_pages(write = 1).
(this is needed for change_pte support in kvm)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 62d2f86..a7151b8 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -156,6 +156,8 @@ module_param(oos_shadow, bool, 0644);
#define CREATE_TRACE_POINTS
#include "mmutrace.h"
+#define SPTE_HOST_WRITEABLE (1ULL<< PT_FIRST_AVAIL_BITS_SHIFT)
+
Luckilly, this bit is available on EPT too.
#define SHADOW_PT_INDEX(addr, level) PT64_I
@@ -595,9 +600,16 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
nr_present++;
pte_access = sp->role.access& FNAME(gpte_access)(vcpu, gpte);
+ if (!(sp->spt[i]& SPTE_HOST_WRITEABLE)) {
+ pte_access&= ~PT_WRITABLE_MASK;
pte_access uses ACC_ masks, not PT_ masks.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
