Re: [PATCH 10/24] Implement VMPTRLD

[Gleb Natapov <gleb@redhat.com>]

On Sun, Jun 13, 2010 at 03:27:41PM +0300, Nadav Har'El wrote:
> This patch implements the VMPTRLD instruction.
> 
> Signed-off-by: Nadav Har'El <nyh@il.ibm.com>
> ---
> --- .before/arch/x86/kvm/vmx.c	2010-06-13 15:01:29.000000000 +0300
> +++ .after/arch/x86/kvm/vmx.c	2010-06-13 15:01:29.000000000 +0300
> @@ -3829,6 +3829,26 @@ static int read_guest_vmcs_gpa(struct kv
>  	return 0;
>  }
>  
> +static void set_rflags_to_vmx_fail_invalid(struct kvm_vcpu *vcpu)
> +{
> +	unsigned long rflags;
> +	rflags = vmx_get_rflags(vcpu);
> +	rflags |= X86_EFLAGS_CF;
> +	rflags &= ~X86_EFLAGS_PF & ~X86_EFLAGS_AF & ~X86_EFLAGS_ZF &
> +		~X86_EFLAGS_SF & ~X86_EFLAGS_OF;
> +	vmx_set_rflags(vcpu, rflags);
> +}
> +
> +static void set_rflags_to_vmx_fail_valid(struct kvm_vcpu *vcpu)
> +{
> +	unsigned long rflags;
> +	rflags = vmx_get_rflags(vcpu);
> +	rflags |= X86_EFLAGS_ZF;
> +	rflags &= ~X86_EFLAGS_PF & ~X86_EFLAGS_AF & ~X86_EFLAGS_CF &
> +		~X86_EFLAGS_SF & ~X86_EFLAGS_OF;
> +	vmx_set_rflags(vcpu, rflags);
> +}
> +
>  static void clear_rflags_cf_zf(struct kvm_vcpu *vcpu)
>  {
>  	unsigned long rflags;
> @@ -3869,6 +3889,57 @@ static int handle_vmclear(struct kvm_vcp
>  	return 1;
>  }
>  
> +static bool verify_vmcs12_revision(struct kvm_vcpu *vcpu, gpa_t guest_vmcs_addr)
> +{
> +	bool ret;
> +	struct vmcs12 *vmcs12;
> +	struct page *vmcs_page = nested_get_page(vcpu, guest_vmcs_addr);
> +	if (vmcs_page == NULL)
> +		return 0;
> +	vmcs12 = (struct vmcs12 *)kmap_atomic(vmcs_page, KM_USER0);
> +	if (vmcs12->revision_id == VMCS12_REVISION)
> +		ret = 1;
> +	else {
> +		set_rflags_to_vmx_fail_valid(vcpu);
Should set VM-Instruction Error Field accordingly.

> +		ret = 0;
> +	}
> +	kunmap_atomic(vmcs12, KM_USER0);
> +	kvm_release_page_dirty(vmcs_page);
> +	return ret;
> +}
> +
> +/* Emulate the VMPTRLD instruction */
> +static int handle_vmptrld(struct kvm_vcpu *vcpu)
> +{
> +	struct vcpu_vmx *vmx = to_vmx(vcpu);
> +	gpa_t guest_vmcs_addr;
> +
> +	if (!nested_vmx_check_permission(vcpu))
> +		return 1;
> +
> +	if (read_guest_vmcs_gpa(vcpu, &guest_vmcs_addr)) {
> +		set_rflags_to_vmx_fail_invalid(vcpu);
> +		return 1;
> +	}
> +
> +	if (!verify_vmcs12_revision(vcpu, guest_vmcs_addr))
> +		return 1;

Should check that guest_vmcs_addr != VMXON address. I think this check
is missing from VMCLEAR too.

> +
> +	if (vmx->nested.current_vmptr != guest_vmcs_addr) {
> +		vmx->nested.current_vmptr = guest_vmcs_addr;
> +
> +		if (nested_create_current_vmcs(vcpu)) {
> +			printk(KERN_ERR "%s error could not allocate memory",
> +				__func__);
> +			return -ENOMEM;
> +		}
> +	}
> +
> +	clear_rflags_cf_zf(vcpu);
> +	skip_emulated_instruction(vcpu);
> +	return 1;
> +}
> +
>  static int handle_invlpg(struct kvm_vcpu *vcpu)
>  {
>  	unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
> @@ -4153,7 +4224,7 @@ static int (*kvm_vmx_exit_handlers[])(st
>  	[EXIT_REASON_VMCALL]                  = handle_vmcall,
>  	[EXIT_REASON_VMCLEAR]	              = handle_vmclear,
>  	[EXIT_REASON_VMLAUNCH]                = handle_vmx_insn,
> -	[EXIT_REASON_VMPTRLD]                 = handle_vmx_insn,
> +	[EXIT_REASON_VMPTRLD]                 = handle_vmptrld,
>  	[EXIT_REASON_VMPTRST]                 = handle_vmx_insn,
>  	[EXIT_REASON_VMREAD]                  = handle_vmx_insn,
>  	[EXIT_REASON_VMRESUME]                = handle_vmx_insn,
> --
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--
			Gleb.