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Subject[PATCH 27/40] KVM: MMU: Replace walk_shadow() by for_each_shadow_entry() in fetch()
Date
Effectively reverting to the pre walk_shadow() version -- but now
with the reusable for_each().

Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/paging_tmpl.h | 128 ++++++++++++++++++++------------------------
1 files changed, 58 insertions(+), 70 deletions(-)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 9fd78b6..69c7e33 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -283,91 +283,79 @@ 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 int FNAME(shadow_walk_entry)(struct kvm_shadow_walk *_sw,
- struct kvm_vcpu *vcpu, u64 addr,
- u64 *sptep, int level)
+static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
+ struct guest_walker *gw,
+ int user_fault, int write_fault, int largepage,
+ int *ptwrite, pfn_t pfn)
{
- 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;
+ u64 spte, *sptep;
int metaphysical;
gfn_t table_gfn;
int r;
+ int level;
pt_element_t curr_pte;
+ struct kvm_shadow_walk_iterator iterator;

- 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->ptes[gw->level-1] & PT_GLOBAL_MASK,
- gw->gfn, sw->pfn, false);
- sw->sptep = sptep;
- return 1;
- }
-
- if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep))
- return 0;
-
- if (is_large_pte(*sptep)) {
- set_shadow_pte(sptep, shadow_trap_nonpresent_pte);
- kvm_flush_remote_tlbs(vcpu->kvm);
- rmap_remove(vcpu->kvm, sptep);
- }
+ if (!is_present_pte(gw->ptes[gw->level - 1]))
+ return NULL;

- 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, (gva_t)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_mmu_put_page(shadow_page, sptep);
- kvm_release_pfn_clean(sw->pfn);
- sw->sptep = NULL;
- return 1;
+ for_each_shadow_entry(vcpu, addr, iterator) {
+ level = iterator.level;
+ sptep = iterator.sptep;
+ if (level == PT_PAGE_TABLE_LEVEL
+ || (largepage && level == PT_DIRECTORY_LEVEL)) {
+ mmu_set_spte(vcpu, sptep, access,
+ gw->pte_access & access,
+ user_fault, write_fault,
+ gw->ptes[gw->level-1] & PT_DIRTY_MASK,
+ ptwrite, largepage,
+ gw->ptes[gw->level-1] & PT_GLOBAL_MASK,
+ gw->gfn, pfn, false);
+ break;
}
- }

- spte = __pa(shadow_page->spt) | PT_PRESENT_MASK | PT_ACCESSED_MASK
- | PT_WRITABLE_MASK | PT_USER_MASK;
- *sptep = spte;
- return 0;
-}
+ if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep))
+ continue;

-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_large_pte(*sptep)) {
+ set_shadow_pte(sptep, shadow_trap_nonpresent_pte);
+ kvm_flush_remote_tlbs(vcpu->kvm);
+ rmap_remove(vcpu->kvm, sptep);
+ }

- if (!is_present_pte(guest_walker->ptes[guest_walker->level - 1]))
- return NULL;
+ 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_mmu_put_page(shadow_page, sptep);
+ kvm_release_pfn_clean(pfn);
+ sptep = NULL;
+ break;
+ }
+ }

- walk_shadow(&walker.walker, vcpu, addr);
+ spte = __pa(shadow_page->spt)
+ | PT_PRESENT_MASK | PT_ACCESSED_MASK
+ | PT_WRITABLE_MASK | PT_USER_MASK;
+ *sptep = spte;
+ }

- return walker.sptep;
+ return sptep;
}

/*
--
1.6.0.6


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