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Date: Wed, 09 Mar 2011 15:43:51 +0800
From: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
To: Avi Kivity <avi@...hat.com>
CC: Marcelo Tosatti <mtosatti@...hat.com>,
LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>
Subject: [PATCH v2 4/4] KVM: MMU: cleanup pte write path
This patch does:
- call vcpu->arch.mmu.update_pte directly
- use gfn_to_pfn_atomic in update_pte path
The suggestion is from Avi.
Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
---
arch/x86/include/asm/kvm_host.h | 7 +---
arch/x86/kvm/mmu.c | 69 +++++++++++++--------------------------
arch/x86/kvm/paging_tmpl.h | 12 ++++---
3 files changed, 32 insertions(+), 56 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f08314f..c8af099 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -255,6 +255,8 @@ struct kvm_mmu {
int (*sync_page)(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp);
void (*invlpg)(struct kvm_vcpu *vcpu, gva_t gva);
+ void (*update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+ u64 *spte, const void *pte, unsigned long mmu_seq);
hpa_t root_hpa;
int root_level;
int shadow_root_level;
@@ -335,11 +337,6 @@ struct kvm_vcpu_arch {
u64 *last_pte_updated;
gfn_t last_pte_gfn;
- struct {
- pfn_t pfn; /* pfn corresponding to that gfn */
- unsigned long mmu_seq;
- } update_pte;
-
struct fpu guest_fpu;
u64 xcr0;
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 83171fd..22fae75 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1204,6 +1204,13 @@ static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
{
}
+static void nonpaging_update_pte(struct kvm_vcpu *vcpu,
+ struct kvm_mmu_page *sp, u64 *spte,
+ const void *pte, unsigned long mmu_seq)
+{
+ WARN_ON(1);
+}
+
#define KVM_PAGE_ARRAY_NR 16
struct kvm_mmu_pages {
@@ -2796,6 +2803,7 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu,
context->prefetch_page = nonpaging_prefetch_page;
context->sync_page = nonpaging_sync_page;
context->invlpg = nonpaging_invlpg;
+ context->update_pte = nonpaging_update_pte;
context->root_level = 0;
context->shadow_root_level = PT32E_ROOT_LEVEL;
context->root_hpa = INVALID_PAGE;
@@ -2925,6 +2933,7 @@ static int paging64_init_context_common(struct kvm_vcpu *vcpu,
context->prefetch_page = paging64_prefetch_page;
context->sync_page = paging64_sync_page;
context->invlpg = paging64_invlpg;
+ context->update_pte = paging64_update_pte;
context->free = paging_free;
context->root_level = level;
context->shadow_root_level = level;
@@ -2953,6 +2962,7 @@ static int paging32_init_context(struct kvm_vcpu *vcpu,
context->prefetch_page = paging32_prefetch_page;
context->sync_page = paging32_sync_page;
context->invlpg = paging32_invlpg;
+ context->update_pte = paging32_update_pte;
context->root_level = PT32_ROOT_LEVEL;
context->shadow_root_level = PT32E_ROOT_LEVEL;
context->root_hpa = INVALID_PAGE;
@@ -2977,6 +2987,7 @@ static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
context->prefetch_page = nonpaging_prefetch_page;
context->sync_page = nonpaging_sync_page;
context->invlpg = nonpaging_invlpg;
+ context->update_pte = nonpaging_update_pte;
context->shadow_root_level = kvm_x86_ops->get_tdp_level();
context->root_hpa = INVALID_PAGE;
context->direct_map = true;
@@ -3081,8 +3092,6 @@ static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
static int init_kvm_mmu(struct kvm_vcpu *vcpu)
{
- vcpu->arch.update_pte.pfn = bad_pfn;
-
if (mmu_is_nested(vcpu))
return init_kvm_nested_mmu(vcpu);
else if (tdp_enabled)
@@ -3156,7 +3165,7 @@ static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp,
u64 *spte,
- const void *new)
+ const void *new, unsigned long mmu_seq)
{
if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
++vcpu->kvm->stat.mmu_pde_zapped;
@@ -3164,10 +3173,7 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
}
++vcpu->kvm->stat.mmu_pte_updated;
- if (!sp->role.cr4_pae)
- paging32_update_pte(vcpu, sp, spte, new);
- else
- paging64_update_pte(vcpu, sp, spte, new);
+ vcpu->arch.mmu.update_pte(vcpu, sp, spte, new, mmu_seq);
}
static bool need_remote_flush(u64 old, u64 new)
@@ -3202,27 +3208,6 @@ static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
return !!(spte && (*spte & shadow_accessed_mask));
}
-static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
- u64 gpte)
-{
- gfn_t gfn;
- pfn_t pfn;
-
- if (!is_present_gpte(gpte))
- return;
- gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
-
- vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
- smp_rmb();
- pfn = gfn_to_pfn(vcpu->kvm, gfn);
-
- if (is_error_pfn(pfn)) {
- kvm_release_pfn_clean(pfn);
- return;
- }
- vcpu->arch.update_pte.pfn = pfn;
-}
-
static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)
{
u64 *spte = vcpu->arch.last_pte_updated;
@@ -3244,21 +3229,14 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
struct kvm_mmu_page *sp;
struct hlist_node *node;
LIST_HEAD(invalid_list);
- u64 entry, gentry;
- u64 *spte;
- unsigned offset = offset_in_page(gpa);
- unsigned pte_size;
- unsigned page_offset;
- unsigned misaligned;
- unsigned quadrant;
- int level;
- int flooded = 0;
- int npte;
- int r;
- int invlpg_counter;
+ unsigned long mmu_seq;
+ u64 entry, gentry, *spte;
+ unsigned pte_size, page_offset, misaligned, quadrant, offset;
+ int level, npte, invlpg_counter, r, flooded = 0;
bool remote_flush, local_flush, zap_page;
zap_page = remote_flush = local_flush = false;
+ offset = offset_in_page(gpa);
pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
@@ -3293,7 +3271,9 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
break;
}
- mmu_guess_page_from_pte_write(vcpu, gpa, gentry);
+ mmu_seq = vcpu->kvm->mmu_notifier_seq;
+ smp_rmb();
+
spin_lock(&vcpu->kvm->mmu_lock);
if (atomic_read(&vcpu->kvm->arch.invlpg_counter) != invlpg_counter)
gentry = 0;
@@ -3365,7 +3345,8 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
if (gentry &&
!((sp->role.word ^ vcpu->arch.mmu.base_role.word)
& mask.word))
- mmu_pte_write_new_pte(vcpu, sp, spte, &gentry);
+ mmu_pte_write_new_pte(vcpu, sp, spte, &gentry,
+ mmu_seq);
if (!remote_flush && need_remote_flush(entry, *spte))
remote_flush = true;
++spte;
@@ -3375,10 +3356,6 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
trace_kvm_mmu_audit(vcpu, AUDIT_POST_PTE_WRITE);
spin_unlock(&vcpu->kvm->mmu_lock);
- if (!is_error_pfn(vcpu->arch.update_pte.pfn)) {
- kvm_release_pfn_clean(vcpu->arch.update_pte.pfn);
- vcpu->arch.update_pte.pfn = bad_pfn;
- }
}
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 86eb816..7514050 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -325,7 +325,7 @@ no_present:
}
static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
- u64 *spte, const void *pte)
+ u64 *spte, const void *pte, unsigned long mmu_seq)
{
pt_element_t gpte;
unsigned pte_access;
@@ -337,12 +337,14 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
- pfn = vcpu->arch.update_pte.pfn;
- if (is_error_pfn(pfn))
+ pfn = gfn_to_pfn_atomic(vcpu->kvm, gpte_to_gfn(gpte));
+ if (is_error_pfn(pfn)) {
+ kvm_release_pfn_clean(pfn);
return;
- if (mmu_notifier_retry(vcpu, vcpu->arch.update_pte.mmu_seq))
+ }
+ if (mmu_notifier_retry(vcpu, mmu_seq))
return;
- kvm_get_pfn(pfn);
+
/*
* we call mmu_set_spte() with host_writable = true beacuse that
* vcpu->arch.update_pte.pfn was fetched from get_user_pages(write = 1).
--
1.7.4
--
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