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Subject[PATCH 28/39] KVM: MMU: Convert the paging mode shadow walk to use the generic walker
Date
From: Avi Kivity <avi@qumranet.com>

Signed-off-by: Avi Kivity <avi@qumranet.com>
---
arch/x86/kvm/paging_tmpl.h | 158 ++++++++++++++++++++++++--------------------
1 files changed, 86 insertions(+), 72 deletions(-)

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index ebb26a0..b7064e1 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -25,6 +25,7 @@
#if PTTYPE == 64
#define pt_element_t u64
#define guest_walker guest_walker64
+ #define shadow_walker shadow_walker64
#define FNAME(name) paging##64_##name
#define PT_BASE_ADDR_MASK PT64_BASE_ADDR_MASK
#define PT_DIR_BASE_ADDR_MASK PT64_DIR_BASE_ADDR_MASK
@@ -41,6 +42,7 @@
#elif PTTYPE == 32
#define pt_element_t u32
#define guest_walker guest_walker32
+ #define shadow_walker shadow_walker32
#define FNAME(name) paging##32_##name
#define PT_BASE_ADDR_MASK PT32_BASE_ADDR_MASK
#define PT_DIR_BASE_ADDR_MASK PT32_DIR_BASE_ADDR_MASK
@@ -71,6 +73,17 @@ struct guest_walker {
u32 error_code;
};

+struct shadow_walker {
+ struct kvm_shadow_walk walker;
+ struct guest_walker *guest_walker;
+ int user_fault;
+ int write_fault;
+ int largepage;
+ int *ptwrite;
+ pfn_t pfn;
+ u64 *sptep;
+};
+
static gfn_t gpte_to_gfn(pt_element_t gpte)
{
return (gpte & PT_BASE_ADDR_MASK) >> PAGE_SHIFT;
@@ -272,86 +285,86 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
/*
* Fetch a shadow pte for a specific level in the paging hierarchy.
*/
-static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
- struct guest_walker *walker,
- int user_fault, int write_fault, int largepage,
- int *ptwrite, pfn_t pfn)
+static int FNAME(shadow_walk_entry)(struct kvm_shadow_walk *_sw,
+ struct kvm_vcpu *vcpu, gva_t addr,
+ u64 *sptep, int level)
{
- hpa_t shadow_addr;
- int level;
- u64 *shadow_ent;
- unsigned access = walker->pt_access;
-
- if (!is_present_pte(walker->ptes[walker->level - 1]))
- return NULL;
-
- shadow_addr = vcpu->arch.mmu.root_hpa;
- level = vcpu->arch.mmu.shadow_root_level;
- if (level == PT32E_ROOT_LEVEL) {
- shadow_addr = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
- shadow_addr &= PT64_BASE_ADDR_MASK;
- --level;
+ struct shadow_walker *sw =
+ container_of(_sw, struct shadow_walker, walker);
+ struct guest_walker *gw = sw->guest_walker;
+ unsigned access = gw->pt_access;
+ struct kvm_mmu_page *shadow_page;
+ u64 spte;
+ int metaphysical;
+ gfn_t table_gfn;
+ int r;
+ pt_element_t curr_pte;
+
+ if (level == PT_PAGE_TABLE_LEVEL
+ || (sw->largepage && level == PT_DIRECTORY_LEVEL)) {
+ mmu_set_spte(vcpu, sptep, access, gw->pte_access & access,
+ sw->user_fault, sw->write_fault,
+ gw->ptes[gw->level-1] & PT_DIRTY_MASK,
+ sw->ptwrite, sw->largepage, gw->gfn, sw->pfn,
+ false);
+ sw->sptep = sptep;
+ return 1;
}

- for (; ; level--) {
- u32 index = SHADOW_PT_INDEX(addr, level);
- struct kvm_mmu_page *shadow_page;
- u64 shadow_pte;
- int metaphysical;
- gfn_t table_gfn;
-
- shadow_ent = ((u64 *)__va(shadow_addr)) + index;
- if (level == PT_PAGE_TABLE_LEVEL)
- break;
-
- if (largepage && level == PT_DIRECTORY_LEVEL)
- break;
-
- if (is_shadow_present_pte(*shadow_ent)
- && !is_large_pte(*shadow_ent)) {
- shadow_addr = *shadow_ent & PT64_BASE_ADDR_MASK;
- continue;
- }
+ if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep))
+ return 0;

- if (is_large_pte(*shadow_ent))
- rmap_remove(vcpu->kvm, shadow_ent);
-
- if (level - 1 == PT_PAGE_TABLE_LEVEL
- && walker->level == PT_DIRECTORY_LEVEL) {
- metaphysical = 1;
- if (!is_dirty_pte(walker->ptes[level - 1]))
- access &= ~ACC_WRITE_MASK;
- table_gfn = gpte_to_gfn(walker->ptes[level - 1]);
- } else {
- metaphysical = 0;
- table_gfn = walker->table_gfn[level - 2];
- }
- shadow_page = kvm_mmu_get_page(vcpu, table_gfn, addr, level-1,
- metaphysical, access,
- shadow_ent);
- if (!metaphysical) {
- int r;
- pt_element_t curr_pte;
- r = kvm_read_guest_atomic(vcpu->kvm,
- walker->pte_gpa[level - 2],
- &curr_pte, sizeof(curr_pte));
- if (r || curr_pte != walker->ptes[level - 2]) {
- kvm_release_pfn_clean(pfn);
- return NULL;
- }
+ if (is_large_pte(*sptep))
+ rmap_remove(vcpu->kvm, sptep);
+
+ if (level == PT_DIRECTORY_LEVEL && gw->level == PT_DIRECTORY_LEVEL) {
+ metaphysical = 1;
+ if (!is_dirty_pte(gw->ptes[level - 1]))
+ access &= ~ACC_WRITE_MASK;
+ table_gfn = gpte_to_gfn(gw->ptes[level - 1]);
+ } else {
+ metaphysical = 0;
+ table_gfn = gw->table_gfn[level - 2];
+ }
+ shadow_page = kvm_mmu_get_page(vcpu, table_gfn, addr, level-1,
+ metaphysical, access, sptep);
+ if (!metaphysical) {
+ r = kvm_read_guest_atomic(vcpu->kvm, gw->pte_gpa[level - 2],
+ &curr_pte, sizeof(curr_pte));
+ if (r || curr_pte != gw->ptes[level - 2]) {
+ kvm_release_pfn_clean(sw->pfn);
+ sw->sptep = NULL;
+ return 1;
}
- shadow_addr = __pa(shadow_page->spt);
- shadow_pte = shadow_addr | PT_PRESENT_MASK | PT_ACCESSED_MASK
- | PT_WRITABLE_MASK | PT_USER_MASK;
- set_shadow_pte(shadow_ent, shadow_pte);
}

- mmu_set_spte(vcpu, shadow_ent, access, walker->pte_access & access,
- user_fault, write_fault,
- walker->ptes[walker->level-1] & PT_DIRTY_MASK,
- ptwrite, largepage, walker->gfn, pfn, false);
+ spte = __pa(shadow_page->spt) | PT_PRESENT_MASK | PT_ACCESSED_MASK
+ | PT_WRITABLE_MASK | PT_USER_MASK;
+ *sptep = spte;
+ return 0;
+}
+
+static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
+ struct guest_walker *guest_walker,
+ int user_fault, int write_fault, int largepage,
+ int *ptwrite, pfn_t pfn)
+{
+ struct shadow_walker walker = {
+ .walker = { .entry = FNAME(shadow_walk_entry), },
+ .guest_walker = guest_walker,
+ .user_fault = user_fault,
+ .write_fault = write_fault,
+ .largepage = largepage,
+ .ptwrite = ptwrite,
+ .pfn = pfn,
+ };
+
+ if (!is_present_pte(guest_walker->ptes[guest_walker->level - 1]))
+ return NULL;
+
+ walk_shadow(&walker.walker, vcpu, addr);

- return shadow_ent;
+ return walker.sptep;
}

/*
@@ -499,6 +512,7 @@ static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu,

#undef pt_element_t
#undef guest_walker
+#undef shadow_walker
#undef FNAME
#undef PT_BASE_ADDR_MASK
#undef PT_INDEX
--
1.6.0.1


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