diff options
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 06cf7e01baf6..72435b1769f6 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6203,26 +6203,34 @@ static void vmx_destroy_pml_buffer(struct vcpu_vmx *vmx) static void vmx_flush_pml_buffer(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); + u16 pml_idx, pml_tail_index; u64 *pml_buf; - u16 pml_idx; + int i; pml_idx = vmcs_read16(GUEST_PML_INDEX); /* Do nothing if PML buffer is empty */ if (pml_idx == PML_HEAD_INDEX) return; + /* + * PML index always points to the next available PML buffer entity + * unless PML log has just overflowed. + */ + pml_tail_index = (pml_idx >= PML_LOG_NR_ENTRIES) ? 0 : pml_idx + 1; - /* PML index always points to next available PML buffer entity */ - if (pml_idx >= PML_LOG_NR_ENTRIES) - pml_idx = 0; - else - pml_idx++; - + /* + * PML log is written backwards: the CPU first writes the entry 511 + * then the entry 510, and so on. + * + * Read the entries in the same order they were written, to ensure that + * the dirty ring is filled in the same order the CPU wrote them. + */ pml_buf = page_address(vmx->pml_pg); - for (; pml_idx < PML_LOG_NR_ENTRIES; pml_idx++) { + + for (i = PML_HEAD_INDEX; i >= pml_tail_index; i--) { u64 gpa; - gpa = pml_buf[pml_idx]; + gpa = pml_buf[i]; WARN_ON(gpa & (PAGE_SIZE - 1)); kvm_vcpu_mark_page_dirty(vcpu, gpa >> PAGE_SHIFT); } |