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Subject[PATCH 4.19 109/131] KVM: nVMX: Plumb L2 GPA through to PML emulation
Date
From: Sean Christopherson <sean.j.christopherson@intel.com>

commit 2dbebf7ae1ed9a420d954305e2c9d5ed39ec57c3 upstream.

Explicitly pass the L2 GPA to kvm_arch_write_log_dirty(), which for all
intents and purposes is vmx_write_pml_buffer(), instead of having the
latter pull the GPA from vmcs.GUEST_PHYSICAL_ADDRESS. If the dirty bit
update is the result of KVM emulation (rare for L2), then the GPA in the
VMCS may be stale and/or hold a completely unrelated GPA.

Fixes: c5f983f6e8455 ("nVMX: Implement emulated Page Modification Logging")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200622215832.22090-2-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/mmu.c | 4 ++--
arch/x86/kvm/mmu.h | 2 +-
arch/x86/kvm/paging_tmpl.h | 7 ++++---
arch/x86/kvm/vmx.c | 5 ++---
5 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 33136395db8fc..ce7b3b22ae86b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1099,7 +1099,7 @@ struct kvm_x86_ops {
void (*enable_log_dirty_pt_masked)(struct kvm *kvm,
struct kvm_memory_slot *slot,
gfn_t offset, unsigned long mask);
- int (*write_log_dirty)(struct kvm_vcpu *vcpu);
+ int (*write_log_dirty)(struct kvm_vcpu *vcpu, gpa_t l2_gpa);

/* pmu operations of sub-arch */
const struct kvm_pmu_ops *pmu_ops;
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 0679303e5f3db..712bc103ef3ad 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1732,10 +1732,10 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
* Emulate arch specific page modification logging for the
* nested hypervisor
*/
-int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu)
+int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu, gpa_t l2_gpa)
{
if (kvm_x86_ops->write_log_dirty)
- return kvm_x86_ops->write_log_dirty(vcpu);
+ return kvm_x86_ops->write_log_dirty(vcpu, l2_gpa);

return 0;
}
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index f7b2de7b6382f..0b62c817f63f5 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -215,7 +215,7 @@ void kvm_mmu_gfn_disallow_lpage(struct kvm_memory_slot *slot, gfn_t gfn);
void kvm_mmu_gfn_allow_lpage(struct kvm_memory_slot *slot, gfn_t gfn);
bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
struct kvm_memory_slot *slot, u64 gfn);
-int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu);
+int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu, gpa_t l2_gpa);

int kvm_mmu_post_init_vm(struct kvm *kvm);
void kvm_mmu_pre_destroy_vm(struct kvm *kvm);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 61f10a4fd8074..8220190b06050 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -202,7 +202,7 @@ static inline unsigned FNAME(gpte_access)(u64 gpte)
static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu,
struct kvm_mmu *mmu,
struct guest_walker *walker,
- int write_fault)
+ gpa_t addr, int write_fault)
{
unsigned level, index;
pt_element_t pte, orig_pte;
@@ -227,7 +227,7 @@ static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu,
!(pte & PT_GUEST_DIRTY_MASK)) {
trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
#if PTTYPE == PTTYPE_EPT
- if (kvm_arch_write_log_dirty(vcpu))
+ if (kvm_arch_write_log_dirty(vcpu, addr))
return -EINVAL;
#endif
pte |= PT_GUEST_DIRTY_MASK;
@@ -424,7 +424,8 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
(PT_GUEST_DIRTY_SHIFT - PT_GUEST_ACCESSED_SHIFT);

if (unlikely(!accessed_dirty)) {
- ret = FNAME(update_accessed_dirty_bits)(vcpu, mmu, walker, write_fault);
+ ret = FNAME(update_accessed_dirty_bits)(vcpu, mmu, walker,
+ addr, write_fault);
if (unlikely(ret < 0))
goto error;
else if (ret)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2c4baff7553b0..f90a9d4d16417 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -13845,11 +13845,10 @@ static void vmx_flush_log_dirty(struct kvm *kvm)
kvm_flush_pml_buffers(kvm);
}

-static int vmx_write_pml_buffer(struct kvm_vcpu *vcpu)
+static int vmx_write_pml_buffer(struct kvm_vcpu *vcpu, gpa_t gpa)
{
struct vmcs12 *vmcs12;
struct vcpu_vmx *vmx = to_vmx(vcpu);
- gpa_t gpa;
struct page *page = NULL;
u64 *pml_address;

@@ -13870,7 +13869,7 @@ static int vmx_write_pml_buffer(struct kvm_vcpu *vcpu)
return 1;
}

- gpa = vmcs_read64(GUEST_PHYSICAL_ADDRESS) & ~0xFFFull;
+ gpa &= ~0xFFFull;

page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->pml_address);
if (is_error_page(page))
--
2.25.1
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