linux-kernel - Re: [PATCH v3 2/2] KVM: s390: selftest: Test suppression indication on key prot exception

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Date:   Tue, 17 May 2022 14:26:19 +0200
From:   Christian Borntraeger <borntraeger@...ux.ibm.com>
To:     Janis Schoetterl-Glausch <scgl@...ux.ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Shuah Khan <shuah@...nel.org>
Cc:     David Hildenbrand <david@...hat.com>, kvm@...r.kernel.org,
        linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] KVM: s390: selftest: Test suppression indication
 on key prot exception



Am 12.05.22 um 15:10 schrieb Janis Schoetterl-Glausch:
> Check that suppression is not indicated on injection of a key checked
> protection exception caused by a memop after it already modified guest
> memory, as that violates the definition of suppression.
> 
> Signed-off-by: Janis Schoetterl-Glausch <scgl@...ux.ibm.com>

Reviewed-by: Christian Borntraeger <borntraeger@...ux.ibm.com>

> ---
>   tools/testing/selftests/kvm/s390x/memop.c | 46 ++++++++++++++++++++++-
>   1 file changed, 45 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/kvm/s390x/memop.c b/tools/testing/selftests/kvm/s390x/memop.c
> index b04c2c1b3c30..49f26f544127 100644
> --- a/tools/testing/selftests/kvm/s390x/memop.c
> +++ b/tools/testing/selftests/kvm/s390x/memop.c
> @@ -10,6 +10,8 @@
>   #include <string.h>
>   #include <sys/ioctl.h>
>   
> +#include <linux/bits.h>
> +
>   #include "test_util.h"
>   #include "kvm_util.h"
>   
> @@ -194,6 +196,7 @@ static int err_memop_ioctl(struct test_vcpu vcpu, struct kvm_s390_mem_op *ksmo)
>   #define SIDA_OFFSET(o) ._sida_offset = 1, .sida_offset = (o)
>   #define AR(a) ._ar = 1, .ar = (a)
>   #define KEY(a) .f_key = 1, .key = (a)
> +#define INJECT .f_inject = 1
>   
>   #define CHECK_N_DO(f, ...) ({ f(__VA_ARGS__, CHECK_ONLY); f(__VA_ARGS__); })
>   
> @@ -430,9 +433,18 @@ static void test_copy_key_fetch_prot(void)
>   	TEST_ASSERT(rv == 4, "Should result in protection exception");		\
>   })
>   
> +static void guest_error_key(void)
> +{
> +	GUEST_SYNC(STAGE_INITED);
> +	set_storage_key_range(mem1, PAGE_SIZE, 0x18);
> +	set_storage_key_range(mem1 + PAGE_SIZE, sizeof(mem1) - PAGE_SIZE, 0x98);
> +	GUEST_SYNC(STAGE_SKEYS_SET);
> +	GUEST_SYNC(STAGE_IDLED);
> +}
> +
>   static void test_errors_key(void)
>   {
> -	struct test_default t = test_default_init(guest_copy_key_fetch_prot);
> +	struct test_default t = test_default_init(guest_error_key);
>   
>   	HOST_SYNC(t.vcpu, STAGE_INITED);
>   	HOST_SYNC(t.vcpu, STAGE_SKEYS_SET);
> @@ -446,6 +458,37 @@ static void test_errors_key(void)
>   	kvm_vm_free(t.kvm_vm);
>   }
>   
> +static void test_termination(void)
> +{
> +	struct test_default t = test_default_init(guest_error_key);
> +	uint64_t prefix;
> +	uint64_t teid;
> +	uint64_t teid_mask = BIT(63 - 56) | BIT(63 - 60) | BIT(63 - 61);
> +	uint64_t psw[2];
> +
> +	HOST_SYNC(t.vcpu, STAGE_INITED);
> +	HOST_SYNC(t.vcpu, STAGE_SKEYS_SET);
> +
> +	/* vcpu, mismatching keys after first page */
> +	ERR_PROT_MOP(t.vcpu, LOGICAL, WRITE, mem1, t.size, GADDR_V(mem1), KEY(1), INJECT);
> +	/*
> +	 * The memop injected a program exception and the test needs to check the
> +	 * Translation-Exception Identification (TEID). It is necessary to run
> +	 * the guest in order to be able to read the TEID from guest memory.
> +	 * Set the guest program new PSW, so the guest state is not clobbered.
> +	 */
> +	prefix = t.run->s.regs.prefix;
> +	psw[0] = t.run->psw_mask;
> +	psw[1] = t.run->psw_addr;
> +	MOP(t.vm, ABSOLUTE, WRITE, psw, sizeof(psw), GADDR(prefix + 464));
> +	HOST_SYNC(t.vcpu, STAGE_IDLED);
> +	MOP(t.vm, ABSOLUTE, READ, &teid, sizeof(teid), GADDR(prefix + 168));
> +	/* Bits 56, 60, 61 form a code, 0 being the only one allowing for termination */
> +	ASSERT_EQ(teid & teid_mask, 0);
> +
> +	kvm_vm_free(t.kvm_vm);
> +}
> +
>   static void test_errors_key_storage_prot_override(void)
>   {
>   	struct test_default t = test_default_init(guest_copy_key_fetch_prot);
> @@ -668,6 +711,7 @@ int main(int argc, char *argv[])
>   		test_copy_key_fetch_prot();
>   		test_copy_key_fetch_prot_override();
>   		test_errors_key();
> +		test_termination();
>   		test_errors_key_storage_prot_override();
>   		test_errors_key_fetch_prot_override_not_enabled();
>   		test_errors_key_fetch_prot_override_enabled();