On Thu, Aug 05, 2010, Avi Kivity wrote about "Re: [PATCH 9/24] Implement VMCLEAR":
> >Do you think it's a good idea to kill
> >the guest immediately, in anticipation of a crash that will most likely
> >come
> >later?
>
> At this stage, the problem is likely to be in the nvmx implementation.
> So it's best to report the problem as early as possible.
Ok, here is the new version of this patch, implementing this case by doing a
triple fault (I hope this is what you meant by KVM_REQ_SHUTDOWN), and also
with other fixes as suggested by you, Gleb and Eddie.
----
Subject: [PATCH 10/26] nVMX: Implement VMCLEAR
This patch implements the VMCLEAR instruction.
Signed-off-by: Nadav Har'El <nyh@xxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 62 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 61 insertions(+), 1 deletion(-)
--- .before/arch/x86/kvm/vmx.c 2010-08-05 15:22:27.000000000 +0300
+++ .after/arch/x86/kvm/vmx.c 2010-08-05 15:22:27.000000000 +0300
@@ -144,6 +144,8 @@ struct __packed vmcs12 {
*/
u32 revision_id;
u32 abort;
+
+ bool launch_state; /* set to 0 by VMCLEAR, to 1 by VMLAUNCH */
};
/*
@@ -3828,6 +3830,64 @@ static void nested_vmx_failValid(struct
get_vmcs12_fields(vcpu)->vm_instruction_error = vm_instruction_error;
}
+/* Emulate the VMCLEAR instruction */
+static int handle_vmclear(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ gva_t gva;
+ gpa_t vmcs12_addr;
+ struct vmcs12 *vmcs12;
+ struct page *page;
+
+ if (!nested_vmx_check_permission(vcpu))
+ return 1;
+
+ if (get_vmx_mem_address(vcpu, vmcs_readl(EXIT_QUALIFICATION),
+ vmcs_read32(VMX_INSTRUCTION_INFO), &gva))
+ return 1;
+
+ if (kvm_read_guest_virt(gva, &vmcs12_addr, sizeof(vmcs12_addr),
+ vcpu, NULL)) {
+ kvm_queue_exception(vcpu, PF_VECTOR);
+ return 1;
+ }
+
+ if (!IS_ALIGNED(vmcs12_addr, PAGE_SIZE)) {
+ nested_vmx_failValid(vcpu, VMXERR_VMCLEAR_INVALID_ADDRESS);
+ skip_emulated_instruction(vcpu);
+ return 1;
+ }
+
+ if (vmcs12_addr == vmx->nested.current_vmptr){
+ kunmap(vmx->nested.current_vmcs12_page);
+ nested_release_page(vmx->nested.current_vmcs12_page);
+ vmx->nested.current_vmptr = -1ull;
+ }
+
+ page = nested_get_page(vcpu, vmcs12_addr);
+ if(page == NULL){
+ /*
+ * For accurate processor emulation, VMCLEAR beyond available
+ * physical memory should do nothing at all. However, it is
+ * possible that a nested vmx bug, not a guest hypervisor bug,
+ * resulted in this case, so let's shut down before doing any
+ * more damage:
+ */
+ set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
+ return 1;
+ }
+ vmcs12 = kmap(page);
+ vmcs12->launch_state = 0;
+ kunmap(page);
+ nested_release_page(page);
+
+ nested_free_vmcs(vcpu, vmcs12_addr);
+
+ skip_emulated_instruction(vcpu);
+ nested_vmx_succeed(vcpu);
+ return 1;
+}
+
static int handle_invlpg(struct kvm_vcpu *vcpu)
{
unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
@@ -4110,7 +4170,7 @@ static int (*kvm_vmx_exit_handlers[])(st
[EXIT_REASON_HLT] = handle_halt,
[EXIT_REASON_INVLPG] = handle_invlpg,
[EXIT_REASON_VMCALL] = handle_vmcall,
- [EXIT_REASON_VMCLEAR] = handle_vmx_insn,
+ [EXIT_REASON_VMCLEAR] = handle_vmclear,
[EXIT_REASON_VMLAUNCH] = handle_vmx_insn,
[EXIT_REASON_VMPTRLD] = handle_vmx_insn,
[EXIT_REASON_VMPTRST] = handle_vmx_insn,
--
Nadav Har'El | Thursday, Aug 5 2010, 25 Av 5770
nyh@xxxxxxxxxxxxxxxxxxx |-----------------------------------------
Phone +972-523-790466, ICQ 13349191 |A fine is a tax for doing wrong. A tax is
http://nadav.harel.org.il |a fine for doing well.
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