On 06/13/2010 03:28 PM, Nadav Har'El wrote:
This patch implements the VMPTRST instruction.
Signed-off-by: Nadav Har'El<nyh@xxxxxxxxxx>
---
--- .before/arch/x86/kvm/x86.c 2010-06-13 15:01:29.000000000 +0300
+++ .after/arch/x86/kvm/x86.c 2010-06-13 15:01:29.000000000 +0300
@@ -3301,7 +3301,7 @@ static int kvm_read_guest_virt_system(gv
return kvm_read_guest_virt_helper(addr, val, bytes, vcpu, 0, error);
}
-static int kvm_write_guest_virt_system(gva_t addr, void *val,
+int kvm_write_guest_virt_system(gva_t addr, void *val,
unsigned int bytes,
struct kvm_vcpu *vcpu,
u32 *error)
write_guest_virt_system() is used by writes which need to ignore the
cpl, for example when a cpl 3 instruction loads a segment, the processor
needs to update the accessed flag even though it is only accessible to
cpl 0. That's not your case, you need the ordinary write_guest_virt().
Um, I see there is no kvm_write_guest_virt(), you'll have to introduce it.
+/* Emulate the VMPTRST instruction */
+static int handle_vmptrst(struct kvm_vcpu *vcpu)
+{
+ int r = 0;
+ unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
+ u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ gva_t vmcs_gva;
+
+ if (!nested_vmx_check_permission(vcpu))
+ return 1;
+
+ vmcs_gva = get_vmx_mem_address(vcpu, exit_qualification,
+ vmx_instruction_info);
+ if (vmcs_gva == 0)
+ return 1;
What's wrong with gva 0? It's favoured by exploiters everywhere.
+ r = kvm_write_guest_virt_system(vmcs_gva,
+ (void *)&to_vmx(vcpu)->nested.current_vmptr,
+ sizeof(u64), vcpu, NULL);
+ if (r) {
Check against the X86EMUL return codes. You'll need to inject a page
fault on failure.
+ printk(KERN_INFO "%s failed to write vmptr\n", __func__);
+ return 1;
+ }
+ clear_rflags_cf_zf(vcpu);
+ skip_emulated_instruction(vcpu);
+ return 1;
+}
+
--
error compiling committee.c: too many arguments to function
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