On Mon, Jun 14, 2010 at 12:36:02PM +0300, Avi Kivity wrote:
> On 06/13/2010 03:29 PM, Nadav Har'El wrote:
> >Implement the VMREAD and VMWRITE instructions. With these instructions, L1
> >can read and write to the VMCS it is holding. The values are read or written
> >to the fields of the shadow_vmcs structure introduced in the previous patch.
> >
> >
> >+
> >+static inline int vmcs_field_size(int field_type, struct kvm_vcpu *vcpu)
> >+{
> >+ switch (field_type) {
> >+ case VMCS_FIELD_TYPE_U16:
> >+ return 2;
> >+ case VMCS_FIELD_TYPE_U32:
> >+ return 4;
> >+ case VMCS_FIELD_TYPE_U64:
> >+ return 8;
> >+ case VMCS_FIELD_TYPE_ULONG:
> >+#ifdef CONFIG_X86_64
> >+ if (is_long_mode(vcpu))
> >+ return 8;
> >+#endif
> >+ return 4;
>
> No need for the ifdef, is_long_mode() works everywhere.
>
> >+ }
> >+ return 0; /* should never happen */
>
> Then BUG()?
>
> >+}
> >+
> > struct vcpu_vmx {
> > struct kvm_vcpu vcpu;
> > struct list_head local_vcpus_link;
> >@@ -4184,6 +4220,189 @@ static int handle_vmclear(struct kvm_vcp
> > return 1;
> > }
> >
> >
> >+static int handle_vmread_reg(struct kvm_vcpu *vcpu, int reg,
> >+ unsigned long field)
> >+{
> >+ u64 field_value;
> >+ if (!nested_vmcs_read_any(vcpu, field,&field_value))
> >+ return 0;
> >+
> >+#ifdef CONFIG_X86_64
> >+ switch (vmcs_field_type(field)) {
> >+ case VMCS_FIELD_TYPE_U64: case VMCS_FIELD_TYPE_ULONG:
> >+ if (!is_long_mode(vcpu)) {
> >+ kvm_register_write(vcpu, reg+1, field_value>> 32);
>
> What's this reg+1 thing? I thought vmread simply ignores the upper half.
>
> >+ field_value = (u32)field_value;
> >+ }
> >+ }
> >+#endif
> >+ kvm_register_write(vcpu, reg, field_value);
> >+ return 1;
> >+}
> >+
> >+static int handle_vmread_mem(struct kvm_vcpu *vcpu, gva_t gva,
> >+ unsigned long field)
> >+{
> >+ u64 field_value;
> >+ if (!nested_vmcs_read_any(vcpu, field,&field_value))
> >+ return 0;
> >+
> >+ /* It's ok to use *_system, because handle_vmread verifies cpl=0 */
>
> >+ kvm_write_guest_virt_system(gva,&field_value,
> >+ vmcs_field_size(vmcs_field_type(field), vcpu),
> >+ vcpu, NULL);
>
> vmread doesn't support 64-bit writes to memory outside long mode, so
> you'll have to truncate the write.
>
> I think you'll be better off returning a 32-bit size in
> vmcs_field_size() in these cases.
>
Actually write should be always 32bit long outside IA-32e mode and
64bit long in 64 bit mode. Unused bits should be set to zero.
> >+ return 1;
> >+}
> >+
> >+static int handle_vmread(struct kvm_vcpu *vcpu)
> >+{
> >+ unsigned long field;
> >+ unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
> >+ u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
> >+ gva_t gva = 0;
> >+ int read_succeed;
> >+
> >+ if (!nested_vmx_check_permission(vcpu))
> >+ return 1;
> >+
> >+ if (!nested_map_current(vcpu)) {
> >+ printk(KERN_INFO "%s invalid shadow vmcs\n", __func__);
> >+ set_rflags_to_vmx_fail_invalid(vcpu);
> >+ return 1;
> >+ }
>
> Can do the read_any() here.
>
> >+
> >+ /* decode instruction info to get the field to read and where to store
> >+ * its value */
> >+ field = kvm_register_read(vcpu, VMX_OPERAND_REG2(vmx_instruction_info));
> >+ if (VMX_OPERAND_IS_REG(vmx_instruction_info)) {
> >+ read_succeed = handle_vmread_reg(vcpu,
> >+ VMX_OPERAND_REG(vmx_instruction_info), field);
> >+ } else {
> >+ gva = get_vmx_mem_address(vcpu, exit_qualification,
> >+ vmx_instruction_info);
> >+ if (gva == 0)
> >+ return 1;
> >+ read_succeed = handle_vmread_mem(vcpu, gva, field);
> >+ }
> >+
> >+ if (read_succeed) {
> >+ clear_rflags_cf_zf(vcpu);
> >+ skip_emulated_instruction(vcpu);
> >+ } else {
> >+ set_rflags_to_vmx_fail_valid(vcpu);
> >+ vmcs_write32(VM_INSTRUCTION_ERROR, 12);
>
> s_e_i() in any case but an exception.
>
> >+ }
> >+
> >+ nested_unmap_current(vcpu);
> >+ return 1;
> >+}
> >+
> >+
> >
> >+ if (VMX_OPERAND_IS_REG(vmx_instruction_info))
> >+ field_value = kvm_register_read(vcpu,
> >+ VMX_OPERAND_REG(vmx_instruction_info));
> >+ else {
> >+ gva = get_vmx_mem_address(vcpu, exit_qualification,
> >+ vmx_instruction_info);
> >+ if (gva == 0)
> >+ return 1;
> >+ kvm_read_guest_virt(gva,&field_value,
> >+ vmcs_field_size(field_type, vcpu), vcpu, NULL);
>
> Check for exception.
>
>
> --
> error compiling committee.c: too many arguments to function
>
> --
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--
Gleb.
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