mmu_need_write_protect() need to be cooked to avoid page becoming writable
when making page table present or sync/prefetch shadow page table entries
Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/kvm_page_track.h | 2 ++
arch/x86/kvm/mmu.c | 44 +++++++++++++++++++++++++++++------
arch/x86/kvm/page_track.c | 14 +++++++++++
arch/x86/kvm/paging_tmpl.h | 3 +++
4 files changed, 56 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/kvm_page_track.h
index 9cc17c6..f223201 100644
--- a/arch/x86/include/asm/kvm_page_track.h
+++ b/arch/x86/include/asm/kvm_page_track.h
@@ -15,4 +15,6 @@ void kvm_page_track_add_page(struct kvm *kvm, gfn_t gfn,
enum kvm_page_track_mode mode);
void kvm_page_track_remove_page(struct kvm *kvm, gfn_t gfn,
enum kvm_page_track_mode mode);
+bool kvm_page_track_check_mode(struct kvm_vcpu *vcpu, gfn_t gfn,
+ enum kvm_page_track_mode mode);
#endif
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 39809b8..b23f9fc 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -41,6 +41,7 @@
#include <asm/cmpxchg.h>
#include <asm/io.h>
#include <asm/vmx.h>
+#include <asm/kvm_page_track.h>
/*
* When setting this variable to true it enables Two-Dimensional-Paging
@@ -2456,25 +2457,29 @@ static void kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn)
}
}
-static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
- bool can_unsync)
+static bool mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
+ bool can_unsync)
{
struct kvm_mmu_page *s;
bool need_unsync = false;
+ if (kvm_page_track_check_mode(vcpu, gfn, KVM_PAGE_TRACK_WRITE))
+ return true;
+
for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
if (!can_unsync)
- return 1;
+ return true;
if (s->role.level != PT_PAGE_TABLE_LEVEL)
- return 1;
+ return true;
if (!s->unsync)
need_unsync = true;
}
if (need_unsync)
kvm_unsync_pages(vcpu, gfn);
- return 0;
+
+ return false;
}
static bool kvm_is_mmio_pfn(pfn_t pfn)
@@ -3388,10 +3393,30 @@ int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct)
}
EXPORT_SYMBOL_GPL(handle_mmio_page_fault);
+static bool page_fault_handle_page_track(struct kvm_vcpu *vcpu,
+ u32 error_code, gfn_t gfn)
+{
+ if (unlikely(error_code & PFERR_RSVD_MASK))
+ return false;
+
+ if (!(error_code & PFERR_PRESENT_MASK) ||
+ !(error_code & PFERR_WRITE_MASK))
+ return false;
+
+ /*
+ * guest is writing the page which is write tracked which can
+ * not be fixed by page fault handler.
+ */
+ if (kvm_page_track_check_mode(vcpu, gfn, KVM_PAGE_TRACK_WRITE))
+ return true;
+
+ return false;
+}
+
static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
u32 error_code, bool prefault)
{
- gfn_t gfn;
+ gfn_t gfn = gva >> PAGE_SHIFT;
int r;
pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
@@ -3403,13 +3428,15 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
return r;
}
+ if (page_fault_handle_page_track(vcpu, error_code, gfn))
+ return 1;
+
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
MMU_WARN_ON(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
- gfn = gva >> PAGE_SHIFT;
return nonpaging_map(vcpu, gva & PAGE_MASK,
error_code, gfn, prefault);
@@ -3493,6 +3520,9 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
return r;
}
+ if (page_fault_handle_page_track(vcpu, error_code, gfn))
+ return 1;
+
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
diff --git a/arch/x86/kvm/page_track.c b/arch/x86/kvm/page_track.c
index ad510db..dc2da12 100644
--- a/arch/x86/kvm/page_track.c
+++ b/arch/x86/kvm/page_track.c
@@ -151,3 +151,17 @@ void kvm_page_track_remove_page(struct kvm *kvm, gfn_t gfn,
spin_unlock(&kvm->mmu_lock);
}
}
+
+/*
+ * check if the corresponding access on the specified guest page is tracked.
+ */
+bool kvm_page_track_check_mode(struct kvm_vcpu *vcpu, gfn_t gfn,
+ enum kvm_page_track_mode mode)
+{
+ struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+ int index = gfn_to_index(gfn, slot->base_gfn, PT_PAGE_TABLE_LEVEL);
+
+ WARN_ON(!check_mode(mode));
+
+ return !!ACCESS_ONCE(slot->arch.gfn_track[mode][index]);
+}
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 91e939b..ac85682 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -735,6 +735,9 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
return 0;
}
+ if (page_fault_handle_page_track(vcpu, error_code, walker.gfn))
+ return 1;
+
vcpu->arch.write_fault_to_shadow_pgtable = false;
is_self_change_mapping = FNAME(is_self_change_mapping)(vcpu,