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KVM: Move first pte address calculation out of loop to save some cycles

PATCH Applied Gui Jianfeng 2 participants 5 messages Apr 16, 2010 – Apr 21, 2010

Subsystems (3)
x86 KVM KVM x86
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Gui Jianfeng

author
#0 lore raw

PATCH 1/4 KVM: Move first pte address calculation out of loop to save some cycles

Move first pte address calculation out of loop to save some cycles

Signed-off-by Gui Jianfeng <[email protected]>
---
 arch/x86/kvm/paging_tmpl.h |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
arch/x86/kvm/paging_tmpl.h +4 -2
index d9dea28..5910557 100644
@@ -572,12 +572,15 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 {
 	int i, offset, nr_present;
 	bool reset_host_protection;
+	gpa_t first_pte_gpa;
 
 	offset = nr_present = 0;
 
 	if (PTTYPE == 32)
 		offset = sp->role.quadrant << PT64_LEVEL_BITS;
 
+	first_pte_gpa = gfn_to_gpa(sp->gfn) + offset * sizeof(pt_element_t);
+
 	for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
 		unsigned pte_access;
 		pt_element_t gpte;

@@ -587,8 +590,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 		if (!is_shadow_present_pte(sp->spt[i]))
 			continue;
 
-		pte_gpa = gfn_to_gpa(sp->gfn);
-		pte_gpa += (i+offset) * sizeof(pt_element_t);
+		pte_gpa = first_pte_gpa + i * sizeof(pt_element_t);
 
 		if (kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &gpte,
 					  sizeof(pt_element_t)))
Signature · 1 line
1.6.5.2
author
#1 lore raw

PATCH 2/4 KVM: Make use of is_large_pte() instead

Make use of is_large_pte() instead of checking PT_PAGE_SIZE_MASK bit directly.

Signed-off-by Gui Jianfeng <[email protected]>
---
 arch/x86/kvm/paging_tmpl.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
arch/x86/kvm/paging_tmpl.h +2 -2
index 5910557..d0cc07e 100644
@@ -190,10 +190,10 @@ walk:
 
 		if ((walker->level == PT_PAGE_TABLE_LEVEL) ||
 		    ((walker->level == PT_DIRECTORY_LEVEL) &&
-				(pte & PT_PAGE_SIZE_MASK)  &&
+				is_large_pte(pte) &&
 				(PTTYPE == 64 || is_pse(vcpu))) ||
 		    ((walker->level == PT_PDPE_LEVEL) &&
-				(pte & PT_PAGE_SIZE_MASK)  &&
+				is_large_pte(pte) &&
 				is_long_mode(vcpu))) {
 			int lvl = walker->level;

-- 1.6.5.2

author
#2 lore raw

PATCH 3/4 KVM: Remove unused varialbe in rmap_next()

In reply to Gui Jianfeng

Remove unused varialbe in rmap_next()

Signed-off-by Gui Jianfeng <[email protected]>
---
 arch/x86/kvm/mmu.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)
arch/x86/kvm/mmu.c +0 -2
index b44380b..dec8a6d 100644
@@ -651,7 +651,6 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
 static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
 {
 	struct kvm_rmap_desc *desc;
-	struct kvm_rmap_desc *prev_desc;
 	u64 *prev_spte;
 	int i;
 

@@ -663,7 +662,6 @@ static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
 		return NULL;
 	}
 	desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
-	prev_desc = NULL;
 	prev_spte = NULL;
 	while (desc) {
 		for (i = 0; i < RMAP_EXT && desc->sptes[i]; ++i) {

-- 1.6.5.2

author
#3 lore raw

PATCH 4/4 KVM: Get rid of dead function

In reply to Gui Jianfeng

Nobody use gva_to_page() anymore, get rid of it.

Signed-off-by Gui Jianfeng <[email protected]>
---
 arch/x86/kvm/mmu.c       |   14 --------------
 include/linux/kvm_host.h |    1 -
 2 files changed, 0 insertions(+), 15 deletions(-)
arch/x86/kvm/mmu.c +0 -14
index dec8a6d..bb18917 100644
@@ -1619,20 +1619,6 @@ static void mmu_convert_notrap(struct kvm_mmu_page *sp)
 	}
 }
 
-struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
-{
-	struct page *page;
-
-	gpa_t gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
-
-	if (gpa == UNMAPPED_GVA)
-		return NULL;
-
-	page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
-
-	return page;
-}
-
 /*
  * The function is based on mtrr_type_lookup() in
  * arch/x86/kernel/cpu/mtrr/generic.c
include/linux/kvm_host.h +0 -1
index 169d077..f1aabe2 100644
@@ -247,7 +247,6 @@ void kvm_put_kvm(struct kvm *kvm);
 #define HPA_MSB ((sizeof(hpa_t) * 8) - 1)
 #define HPA_ERR_MASK ((hpa_t)1 << HPA_MSB)
 static inline int is_error_hpa(hpa_t hpa) { return hpa >> HPA_MSB; }
-struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva);
 
 extern struct page *bad_page;
 extern pfn_t bad_pfn;

-- 1.6.5.2

Applied
#4 lore raw
In reply to Gui Jianfeng
Quoted 2 lines · Gui Jianfeng

Move first pte address calculation out of loop to save some cycles

Applied all four patches, thanks.

Signature · 1 line
error compiling committee.c: too many arguments to function