[PATCH v2 08/10] KVM: do not release the error pfn

Xiao Guangrong
2012-08-03T07:42:26Z

After commit a2766325cf9f9, the error pfn is replaced by the
error code, it need not be released anymore

[ The patch has been compiling tested for powerpc ]

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
arch/powerpc/kvm/e500_tlb.c | 1 -
arch/x86/kvm/mmu.c | 7 +++----
arch/x86/kvm/mmu_audit.c | 4 +---
arch/x86/kvm/paging_tmpl.h | 8 ++------
virt/kvm/iommu.c | 1 -
virt/kvm/kvm_main.c | 14 ++++++++------
6 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/arch/powerpc/kvm/e500_tlb.c b/arch/powerpc/kvm/e500_tlb.c
index c8f6c58..09ce5ac 100644
--- a/arch/powerpc/kvm/e500_tlb.c
+++ b/arch/powerpc/kvm/e500_tlb.c
@@ -524,7 +524,6 @@ static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
if (is_error_pfn(pfn)) {
printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
(long)gfn);
- kvm_release_pfn_clean(pfn);
return;
}

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 924b4e8..d68223f 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2498,7 +2498,9 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
rmap_recycle(vcpu, sptep, gfn);
}
}
- kvm_release_pfn_clean(pfn);
+
+ if (!is_error_pfn(pfn))
+ kvm_release_pfn_clean(pfn);
}

static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
@@ -2650,7 +2652,6 @@ static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *

static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, pfn_t pfn)
{
- kvm_release_pfn_clean(pfn);
if (pfn == KVM_PFN_ERR_HWPOISON) {
kvm_send_hwpoison_signal(gfn_to_hva(vcpu->kvm, gfn), current);
return 0;
@@ -3275,8 +3276,6 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
if (!async)
return false; /* *pfn has correct page already */

- kvm_release_pfn_clean(*pfn);
-
if (!prefault && can_do_async_pf(vcpu)) {
trace_kvm_try_async_get_page(gva, gfn);
if (kvm_find_async_pf_gfn(vcpu, gfn)) {
diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index 7d7d0b9..bac5fa4 100644
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -116,10 +116,8 @@ static void audit_mappings(struct kvm_vcpu *vcpu, u64 *sptep, int level)
gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
pfn = gfn_to_pfn_atomic(vcpu->kvm, gfn);

- if (is_error_pfn(pfn)) {
- kvm_release_pfn_clean(pfn);
+ if (is_error_pfn(pfn))
return;
- }

hpa = pfn << PAGE_SHIFT;
if ((*sptep & PT64_BASE_ADDR_MASK) != hpa)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index bb7cf01..bf8c42b 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -370,10 +370,8 @@ 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, true);
pfn = gfn_to_pfn_atomic(vcpu->kvm, gpte_to_gfn(gpte));
- if (mmu_invalid_pfn(pfn)) {
- kvm_release_pfn_clean(pfn);
+ if (mmu_invalid_pfn(pfn))
return;
- }

/*
* we call mmu_set_spte() with host_writable = true because that
@@ -448,10 +446,8 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
gfn = gpte_to_gfn(gpte);
pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn,
pte_access & ACC_WRITE_MASK);
- if (mmu_invalid_pfn(pfn)) {
- kvm_release_pfn_clean(pfn);
+ if (mmu_invalid_pfn(pfn))
break;
- }

mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0,
NULL, PT_PAGE_TABLE_LEVEL, gfn,
diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index 6a67bea..037cb67 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -107,7 +107,6 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
*/
pfn = kvm_pin_pages(slot, gfn, page_size);
if (is_error_pfn(pfn)) {
- kvm_release_pfn_clean(pfn);
gfn += 1;
continue;
}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5873031..bd175f7 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -102,9 +102,6 @@ static bool largepages_enabled = true;

bool kvm_is_mmio_pfn(pfn_t pfn)
{
- if (is_error_pfn(pfn))
- return false;
-
if (pfn_valid(pfn)) {
int reserved;
struct page *tail = pfn_to_page(pfn);
@@ -1174,10 +1171,13 @@ EXPORT_SYMBOL_GPL(gfn_to_page_many_atomic);

static struct page *kvm_pfn_to_page(pfn_t pfn)
{
- WARN_ON(kvm_is_mmio_pfn(pfn));
+ if (is_error_pfn(pfn))
+ return KVM_ERR_PTR_BAD_PAGE;

- if (is_error_pfn(pfn) || kvm_is_mmio_pfn(pfn))
+ if (kvm_is_mmio_pfn(pfn)) {
+ WARN_ON(1);
return KVM_ERR_PTR_BAD_PAGE;
+ }

return pfn_to_page(pfn);
}
@@ -1202,7 +1202,9 @@ EXPORT_SYMBOL_GPL(kvm_release_page_clean);

void kvm_release_pfn_clean(pfn_t pfn)
{
- if (!is_error_pfn(pfn) && !kvm_is_mmio_pfn(pfn))
+ WARN_ON(is_error_pfn(pfn));
+
+ if (!kvm_is_mmio_pfn(pfn))
put_page(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
--
1.7.7.6