[PATCH v2 15/22] KVM: MMU: abstract some functions to handle fault pfn

Xiao Guangrong
2011-06-22T14:34:01Z

Introduce handle_abnormal_pfn to handle fault pfn on page fault path,
introduce mmu_invalid_pfn to handle fault pfn on prefetch path

It is the preparing work for mmio page fault support

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
arch/x86/kvm/mmu.c | 47 ++++++++++++++++++++++++++++++++-----------
arch/x86/kvm/paging_tmpl.h | 12 +++++-----
2 files changed, 41 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 4a51042..4fe1cb3 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2221,18 +2221,15 @@ static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *
send_sig_info(SIGBUS, &info, tsk);
}

-static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gva_t gva,
- unsigned access, gfn_t gfn, pfn_t pfn)
+static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, pfn_t pfn)
{
kvm_release_pfn_clean(pfn);
if (is_hwpoison_pfn(pfn)) {
kvm_send_hwpoison_signal(gfn_to_hva(vcpu->kvm, gfn), current);
return 0;
- } else if (is_fault_pfn(pfn))
- return -EFAULT;
+ }

- vcpu_cache_mmio_info(vcpu, gva, gfn, access);
- return 1;
+ return -EFAULT;
}

static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
@@ -2277,6 +2274,33 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
}
}

+static bool mmu_invalid_pfn(pfn_t pfn)
+{
+ return unlikely(is_invalid_pfn(pfn) || is_mmio_pfn(pfn));
+}
+
+static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
+ pfn_t pfn, unsigned access, int *ret_val)
+{
+ bool ret = true;
+
+ /* The pfn is invalid, report the error! */
+ if (unlikely(is_invalid_pfn(pfn))) {
+ *ret_val = kvm_handle_bad_page(vcpu, gfn, pfn);
+ goto exit;
+ }
+
+ if (unlikely(is_mmio_pfn(pfn))) {
+ vcpu_cache_mmio_info(vcpu, gva, gfn, access);
+ *ret_val = 1;
+ goto exit;
+ }
+
+ ret = false;
+exit:
+ return ret;
+}
+
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
gva_t gva, pfn_t *pfn, bool write, bool *writable);

@@ -2311,9 +2335,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn,
if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write, &map_writable))
return 0;

- /* mmio */
- if (is_error_pfn(pfn))
- return kvm_handle_bad_page(vcpu, v, ACC_ALL, gfn, pfn);
+ if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r))
+ return r;

spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
@@ -2685,9 +2708,9 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable))
return 0;

- /* mmio */
- if (is_error_pfn(pfn))
- return kvm_handle_bad_page(vcpu, 0, 0, gfn, pfn);
+ if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r))
+ return r;
+
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
goto out_unlock;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 58a29d0..870be69 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -373,7 +373,7 @@ 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 (is_error_pfn(pfn)) {
+ if (mmu_invalid_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
return;
}
@@ -451,7 +451,7 @@ 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 (is_error_pfn(pfn)) {
+ if (mmu_invalid_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
break;
}
@@ -621,10 +621,10 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
&map_writable))
return 0;

- /* mmio */
- if (is_error_pfn(pfn))
- return kvm_handle_bad_page(vcpu, mmu_is_nested(vcpu) ? 0 :
- addr, walker.pte_access, walker.gfn, pfn);
+ if (handle_abnormal_pfn(vcpu, mmu_is_nested(vcpu) ? 0 : addr,
+ walker.gfn, pfn, walker.pte_access, &r))
+ return r;
+
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
goto out_unlock;
--
1.7.5.4