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Subject[PATCH v2 03/12] zap sp if it is written by unaware instructions
Drop the shadow page if it is written by the instructions which is not
typically used to modify the page table

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
arch/x86/include/asm/kvm_host.h | 4 ++--
arch/x86/kvm/mmu.c | 6 +++---
arch/x86/kvm/paging_tmpl.h | 3 ++-
arch/x86/kvm/x86.c | 11 +++++++----
4 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 307e3cf..a386755 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -664,7 +664,7 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages);
int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3);

int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
- const void *val, int bytes);
+ const void *val, int bytes, bool page_table_written);
int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
gpa_t addr, unsigned long *ret);
u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn);
@@ -750,7 +750,7 @@ int fx_init(struct kvm_vcpu *vcpu);
void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu);
void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *new, int bytes,
- bool guest_initiated);
+ bool guest_initiated, bool page_table_written);
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva);
void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
int kvm_mmu_load(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 28991b2..82d5d5a 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3541,7 +3541,7 @@ static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)

void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *new, int bytes,
- bool guest_initiated)
+ bool guest_initiated, bool page_table_written)
{
gfn_t gfn = gpa >> PAGE_SHIFT;
union kvm_mmu_page_role mask = { .word = 0 };
@@ -3627,7 +3627,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
pte_size = sp->role.cr4_pae ? 8 : 4;
misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
misaligned |= bytes < 4;
- if (misaligned || flooded) {
+ if (misaligned || flooded || !page_table_written) {
/*
* Misaligned accesses are too much trouble to fix
* up; also, they usually indicate a page is not used
@@ -4008,7 +4008,7 @@ static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
if (r)
return r;

- if (!emulator_write_phys(vcpu, addr, &value, bytes))
+ if (!emulator_write_phys(vcpu, addr, &value, bytes, true))
return -EFAULT;

return 1;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 507e2b8..5edbba6 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -710,7 +710,8 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)

if (mmu_topup_memory_caches(vcpu))
return;
- kvm_mmu_pte_write(vcpu, pte_gpa, NULL, sizeof(pt_element_t), 0);
+ kvm_mmu_pte_write(vcpu, pte_gpa, NULL, sizeof(pt_element_t),
+ false, true);
}

static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr, u32 access,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cf6fb29..fbb3a44 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4058,14 +4058,14 @@ static int vcpu_mmio_gva_to_gpa(struct kvm_vcpu *vcpu, unsigned long gva,
}

int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
- const void *val, int bytes)
+ const void *val, int bytes, bool page_table_written)
{
int ret;

ret = kvm_write_guest(vcpu->kvm, gpa, val, bytes);
if (ret < 0)
return 0;
- kvm_mmu_pte_write(vcpu, gpa, val, bytes, 1);
+ kvm_mmu_pte_write(vcpu, gpa, val, bytes, true, page_table_written);
return 1;
}

@@ -4103,7 +4103,10 @@ static int read_emulate(struct kvm_vcpu *vcpu, gpa_t gpa,
static int write_emulate(struct kvm_vcpu *vcpu, gpa_t gpa,
void *val, int bytes)
{
- return emulator_write_phys(vcpu, gpa, val, bytes);
+ struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
+
+ return emulator_write_phys(vcpu, gpa, val, bytes,
+ ctxt->page_table_written_insn);
}

static int write_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes, void *val)
@@ -4302,7 +4305,7 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
if (!exchanged)
return X86EMUL_CMPXCHG_FAILED;

- kvm_mmu_pte_write(vcpu, gpa, new, bytes, 1);
+ kvm_mmu_pte_write(vcpu, gpa, new, bytes, true, true);

return X86EMUL_CONTINUE;

--
1.7.5.4


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