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KVM: MMU: combine guest pte read between fetch and pte prefetch

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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>
This commit is contained in:
Xiao Guangrong
2010-08-22 19:13:33 +08:00
committed by Avi Kivity
parent 957ed9effd
commit 189be38db3
1 changed files with 20 additions and 18 deletions
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38
arch/x86/kvm/paging_tmpl.h
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@@ -67,6 +67,7 @@ struct guest_walker {
int level; int level;
gfn_t table_gfn[PT_MAX_FULL_LEVELS]; gfn_t table_gfn[PT_MAX_FULL_LEVELS];
pt_element_t ptes[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]; gpa_t pte_gpa[PT_MAX_FULL_LEVELS];
unsigned pt_access; unsigned pt_access;
unsigned pte_access; unsigned pte_access;
@@ -302,21 +303,33 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu, static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu,
struct guest_walker *gw, int level) struct guest_walker *gw, int level)
{ {
int r;
pt_element_t curr_pte; 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)); &curr_pte, sizeof(curr_pte));
return r || curr_pte != gw->ptes[level - 1]; 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; struct kvm_mmu_page *sp;
pt_element_t gptep[PTE_PREFETCH_NUM]; pt_element_t *gptep = gw->prefetch_ptes;
gpa_t first_pte_gpa;
int offset = 0, i;
u64 *spte; u64 *spte;
int i;
sp = page_header(__pa(sptep)); sp = page_header(__pa(sptep));
@@ -327,17 +340,6 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, u64 *sptep)
return __direct_pte_prefetch(vcpu, sp, sptep); return __direct_pte_prefetch(vcpu, sp, sptep);
i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1); 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; spte = sp->spt + i;
for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) { for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
@@ -462,7 +464,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
mmu_set_spte(vcpu, it.sptep, access, gw->pte_access & access, mmu_set_spte(vcpu, it.sptep, access, gw->pte_access & access,
user_fault, write_fault, dirty, ptwrite, it.level, user_fault, write_fault, dirty, ptwrite, it.level,
gw->gfn, pfn, false, true); gw->gfn, pfn, false, true);
FNAME(pte_prefetch)(vcpu, it.sptep); FNAME(pte_prefetch)(vcpu, gw, it.sptep);
return it.sptep; return it.sptep;