KVM: MMU: combine guest pte read between fetch and pte prefetch
Combine guest pte read between guest pte check in the fetch path and pte prefetch
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 872ff26..a4e8389 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -67,6 +67,7 @@
int level;
gfn_t table_gfn[PT_MAX_FULL_LEVELS];
pt_element_t ptes[PT_MAX_FULL_LEVELS];
+ pt_element_t prefetch_ptes[PTE_PREFETCH_NUM];
gpa_t pte_gpa[PT_MAX_FULL_LEVELS];
unsigned pt_access;
unsigned pte_access;
@@ -302,21 +303,33 @@
static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu,
struct guest_walker *gw, int level)
{
- int r;
pt_element_t curr_pte;
+ gpa_t base_gpa, pte_gpa = gw->pte_gpa[level - 1];
+ u64 mask;
+ int r, index;
- r = kvm_read_guest_atomic(vcpu->kvm, gw->pte_gpa[level - 1],
+ if (level == PT_PAGE_TABLE_LEVEL) {
+ mask = PTE_PREFETCH_NUM * sizeof(pt_element_t) - 1;
+ base_gpa = pte_gpa & ~mask;
+ index = (pte_gpa - base_gpa) / sizeof(pt_element_t);
+
+ r = kvm_read_guest_atomic(vcpu->kvm, base_gpa,
+ gw->prefetch_ptes, sizeof(gw->prefetch_ptes));
+ curr_pte = gw->prefetch_ptes[index];
+ } else
+ r = kvm_read_guest_atomic(vcpu->kvm, pte_gpa,
&curr_pte, sizeof(curr_pte));
+
return r || curr_pte != gw->ptes[level - 1];
}
-static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, u64 *sptep)
+static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
+ u64 *sptep)
{
struct kvm_mmu_page *sp;
- pt_element_t gptep[PTE_PREFETCH_NUM];
- gpa_t first_pte_gpa;
- int offset = 0, i;
+ pt_element_t *gptep = gw->prefetch_ptes;
u64 *spte;
+ int i;
sp = page_header(__pa(sptep));
@@ -327,17 +340,6 @@
return __direct_pte_prefetch(vcpu, sp, sptep);
i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1);
-
- if (PTTYPE == 32)
- offset = sp->role.quadrant << PT64_LEVEL_BITS;
-
- first_pte_gpa = gfn_to_gpa(sp->gfn) +
- (offset + i) * sizeof(pt_element_t);
-
- if (kvm_read_guest_atomic(vcpu->kvm, first_pte_gpa, gptep,
- sizeof(gptep)) < 0)
- return;
-
spte = sp->spt + i;
for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
@@ -462,7 +464,7 @@
mmu_set_spte(vcpu, it.sptep, access, gw->pte_access & access,
user_fault, write_fault, dirty, ptwrite, it.level,
gw->gfn, pfn, false, true);
- FNAME(pte_prefetch)(vcpu, it.sptep);
+ FNAME(pte_prefetch)(vcpu, gw, it.sptep);
return it.sptep;
