[PATCH v4 3/5] KVM: MMU: cleanup FNAME(page_fault)

Xiao Guangrong
2012-10-07T12:02:47Z

Let it return emulate state instead of spte like __direct_map

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
arch/x86/kvm/paging_tmpl.h | 32 +++++++++++++-------------------
1 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 045d31a..c555532 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -427,21 +427,21 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,

/*
* Fetch a shadow pte for a specific level in the paging hierarchy.
+ * If the guest tries to write a write-protected page, we need to
+ * emulate this operation, return 1 to indicate this case.
*/
-static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
+static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
struct guest_walker *gw,
int user_fault, int write_fault, int hlevel,
- int *emulate, pfn_t pfn, bool map_writable,
- bool prefault)
+ pfn_t pfn, bool map_writable, bool prefault)
{
- unsigned access = gw->pt_access;
struct kvm_mmu_page *sp = NULL;
- int top_level;
- unsigned direct_access;
struct kvm_shadow_walk_iterator it;
+ unsigned direct_access, access = gw->pt_access;
+ int top_level, emulate = 0;

if (!is_present_gpte(gw->ptes[gw->level - 1]))
- return NULL;
+ return 0;

direct_access = gw->pte_access;

@@ -505,17 +505,17 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,

clear_sp_write_flooding_count(it.sptep);
mmu_set_spte(vcpu, it.sptep, access, gw->pte_access,
- user_fault, write_fault, emulate, it.level,
+ user_fault, write_fault, &emulate, it.level,
gw->gfn, pfn, prefault, map_writable);
FNAME(pte_prefetch)(vcpu, gw, it.sptep);

- return it.sptep;
+ return emulate;

out_gpte_changed:
if (sp)
kvm_mmu_put_page(sp, it.sptep);
kvm_release_pfn_clean(pfn);
- return NULL;
+ return 0;
}

/*
@@ -538,8 +538,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
int write_fault = error_code & PFERR_WRITE_MASK;
int user_fault = error_code & PFERR_USER_MASK;
struct guest_walker walker;
- u64 *sptep;
- int emulate = 0;
int r;
pfn_t pfn;
int level = PT_PAGE_TABLE_LEVEL;
@@ -601,17 +599,13 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
kvm_mmu_free_some_pages(vcpu);
if (!force_pt_level)
transparent_hugepage_adjust(vcpu, &walker.gfn, &pfn, &level);
- sptep = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
- level, &emulate, pfn, map_writable, prefault);
- (void)sptep;
- pgprintk("%s: shadow pte %p %llx emulate %d\n", __func__,
- sptep, *sptep, emulate);
-
+ r = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
+ level, pfn, map_writable, prefault);
++vcpu->stat.pf_fixed;
kvm_mmu_audit(vcpu, AUDIT_POST_PAGE_FAULT);
spin_unlock(&vcpu->kvm->mmu_lock);

- return emulate;
+ return r;

out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
--
1.7.7.6