linux-kernel - Re: [PATCH v2 2/2] KVM: s390: selftest: Test suppression indication on key prot exception

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Date:   Thu, 28 Apr 2022 18:48:57 +0200
From:   Janis Schoetterl-Glausch <scgl@...ux.ibm.com>
To:     Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>
Cc:     David Hildenbrand <david@...hat.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>,
        Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        Shuah Khan <shuah@...nel.org>, linux-kselftest@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org
Subject: Re: [PATCH v2 2/2] KVM: s390: selftest: Test suppression indication
 on key prot exception

On 4/25/22 12:01, Janis Schoetterl-Glausch wrote:
> 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>
> ---
>  tools/testing/selftests/kvm/s390x/memop.c | 43 ++++++++++++++++++++++-
>  1 file changed, 42 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/kvm/s390x/memop.c b/tools/testing/selftests/kvm/s390x/memop.c
> index b04c2c1b3c30..ce176ad9f216 100644
> --- a/tools/testing/selftests/kvm/s390x/memop.c
> +++ b/tools/testing/selftests/kvm/s390x/memop.c

[...]

> +static void test_termination(void)
> +{
> +	struct test_default t = test_default_init(guest_error_key);
> +	uint64_t prefix;
> +	uint64_t teid;
> +	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 & 0x4c, 0);

The constant is wrong, should be 0x8c instead, or better, a more straight forward
expression that evaluates to it.

[...]