Re: [kvm-unit-tests v4 4/4] x86: Add test case for INVVPID with LAM

[Binbin Wu <binbin.wu@linux.intel.com>]

On 5/4/2023 4:47 PM, Binbin Wu wrote:
> When LAM is on, the linear address of INVVPID operand can contain
> metadata, and the linear address in the INVVPID descriptor can
> contain metadata.
>
> The added cases use tagged descriptor address or/and tagged target
> invalidation address to make sure the behaviors are expected when
> LAM is on.
> Also, INVVPID cases can be used as the common test cases for VMX
> instruction VMExits.
>
> Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
> Reviewed-by: Chao Gao <chao.gao@intel.com>
> ---
>   x86/vmx_tests.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 51 insertions(+), 1 deletion(-)
>
> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
> index 217befe..678c9ec 100644
> --- a/x86/vmx_tests.c
> +++ b/x86/vmx_tests.c
> @@ -3225,6 +3225,54 @@ static void invvpid_test_not_in_vmx_operation(void)
>   	TEST_ASSERT(!vmx_on());
>   }
>   
> +/* LAM applies to the target address inside the descriptor of invvpid */
> +static void invvpid_test_lam(void)
> +{
> +	void *vaddr;
> +	struct invvpid_operand *operand;
> +	u64 lam_mask = LAM48_MASK;
> +	bool fault;
> +
> +	if (!this_cpu_has(X86_FEATURE_LAM)) {
> +		report_skip("LAM is not supported, skip INVVPID with LAM");
> +		return;
> +	}
> +	write_cr4_safe(read_cr4() | X86_CR4_LAM_SUP);
> +
> +	if (this_cpu_has(X86_FEATURE_LA57) && read_cr4() & X86_CR4_LA57)
> +		lam_mask = LAM57_MASK;
> +
> +	vaddr = alloc_vpage();
> +	install_page(current_page_table(), virt_to_phys(alloc_page()), vaddr);
> +	/*
> +	 * Since the stack memory address in KUT doesn't follow kernel address
> +	 * space partition rule, reuse the memory address for descriptor and
> +	 * the target address in the descriptor of invvpid.
> +	 */
> +	operand = (struct invvpid_operand *)vaddr;
> +	operand->vpid = 0xffff;
> +	operand->gla = (u64)vaddr;
> +
> +	operand = (struct invvpid_operand *)vaddr;
> +	operand->gla = set_la_non_canonical(operand->gla, lam_mask);
> +	fault = test_for_exception(GP_VECTOR, ds_invvpid, operand);
> +	report(!fault, "INVVPID (LAM on): untagged pointer + tagged addr");
> +
> +	operand = (struct invvpid_operand *)set_la_non_canonical((u64)operand,
> +								 lam_mask);
> +	operand->gla = (u64)vaddr;
> +	fault = test_for_exception(GP_VECTOR, ds_invvpid, operand);
> +	report(!fault, "INVVPID (LAM on): tagged pointer + untagged addr");
> +
> +	operand = (struct invvpid_operand *)set_la_non_canonical((u64)operand,
> +								 lam_mask);
> +	operand->gla = set_la_non_canonical(operand->gla, lam_mask);
> +	fault = test_for_exception(GP_VECTOR, ds_invvpid, operand);
> +	report(!fault, "INVVPID (LAM on): tagged pointer + tagged addr");
The test cases designed for invvpid with LAM is not right.

Will use two test cases to test invvpid when LAM is activated:
One to test with tagged operand expecting no #GP.
The other one to test with tagged target address inside the descriptor 
expecting failure and VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID set in 
VMX_INST_ERROR field of VMCS.

The new test code proposed as below:

     ....
     operand = (struct invvpid_operand *)vaddr;
     operand->vpid = 0xffff;
     operand->gla = (u64)vaddr;
     operand = (struct invvpid_operand *)set_la_non_canonical((u64)operand,
                                  lam_mask);
     fault = test_for_exception(GP_VECTOR, ds_invvpid, operand);
     report(!fault, "INVVPID (LAM on): tagged operand");

     /*
      * LAM doesn't apply to the address inside the descriptor, expected
      * failure and VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID set in
      * VMX_INST_ERROR.
      */
     try_invvpid(INVVPID_ADDR, 0xffff, NONCANONICAL);


> +
> +	write_cr4_safe(read_cr4() & ~X86_CR4_LAM_SUP);
> +}
> +
>   /*
>    * This does not test real-address mode, virtual-8086 mode, protected mode,
>    * or CPL > 0.
> @@ -3274,8 +3322,10 @@ static void invvpid_test(void)
>   	/*
>   	 * The gla operand is only validated for single-address INVVPID.
>   	 */
> -	if (types & (1u << INVVPID_ADDR))
> +	if (types & (1u << INVVPID_ADDR)) {
>   		try_invvpid(INVVPID_ADDR, 0xffff, NONCANONICAL);
> +		invvpid_test_lam();
> +	}
>   
>   	invvpid_test_gp();
>   	invvpid_test_ss();