Re: [PATCH] KVM: selftests: Add coverage of MTE system registers
From: Marc Zyngier
Date: Sun Mar 12 2023 - 06:32:44 EST
On Wed, 08 Mar 2023 17:12:26 +0000,
Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> Verify that a guest with MTE has access to the MTE registers. Since MTE is
> enabled as a VM wide capability we need to add support for doing that in
> the process.
>
> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
> ---
> tools/testing/selftests/kvm/aarch64/get-reg-list.c | 33 ++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/aarch64/get-reg-list.c b/tools/testing/selftests/kvm/aarch64/get-reg-list.c
> index d287dd2cac0a..63d6a9046702 100644
> --- a/tools/testing/selftests/kvm/aarch64/get-reg-list.c
> +++ b/tools/testing/selftests/kvm/aarch64/get-reg-list.c
> @@ -42,6 +42,7 @@ struct reg_sublist {
> long capability;
> int feature;
> bool finalize;
> + bool enable_capability;
> __u64 *regs;
> __u64 regs_n;
> __u64 *rejects_set;
> @@ -404,6 +405,18 @@ static void check_supported(struct vcpu_config *c)
> }
> }
>
> +static void enable_capabilities(struct kvm_vm *vm, struct vcpu_config *c)
> +{
> + struct reg_sublist *s;
> +
> + for_each_sublist(c, s) {
> + if (!s->enable_capability)
> + continue;
> +
> + vm_enable_cap(vm, s->capability, 1);
> + }
> +}
> +
> static bool print_list;
> static bool print_filtered;
> static bool fixup_core_regs;
> @@ -420,6 +433,7 @@ static void run_test(struct vcpu_config *c)
> check_supported(c);
>
> vm = vm_create_barebones();
> + enable_capabilities(vm, c);
> prepare_vcpu_init(c, &init);
> vcpu = __vm_vcpu_add(vm, 0);
> aarch64_vcpu_setup(vcpu, &init);
> @@ -1049,6 +1063,13 @@ static __u64 pauth_generic_regs[] = {
> ARM64_SYS_REG(3, 0, 2, 3, 1), /* APGAKEYHI_EL1 */
> };
>
> +static __u64 mte_regs[] = {
> + ARM64_SYS_REG(3, 0, 1, 0, 5), /* RGSR_EL1 */
> + ARM64_SYS_REG(3, 0, 1, 0, 6), /* GCR_EL1 */
> + ARM64_SYS_REG(3, 0, 5, 6, 0), /* TFSR_EL1 */
> + ARM64_SYS_REG(3, 0, 5, 6, 1), /* TFSRE0_EL1 */
> +};
> +
> #define BASE_SUBLIST \
> { "base", .regs = base_regs, .regs_n = ARRAY_SIZE(base_regs), }
> #define VREGS_SUBLIST \
> @@ -1075,6 +1096,9 @@ static __u64 pauth_generic_regs[] = {
> .regs = pauth_generic_regs, \
> .regs_n = ARRAY_SIZE(pauth_generic_regs), \
> }
> +#define MTE_SUBLIST \
> + { "mte", .capability = KVM_CAP_ARM_MTE, .enable_capability = true, \
> + .regs = mte_regs, .regs_n = ARRAY_SIZE(mte_regs), }
>
> static struct vcpu_config vregs_config = {
> .sublists = {
> @@ -1123,6 +1147,14 @@ static struct vcpu_config pauth_pmu_config = {
> {0},
> },
> };
> +static struct vcpu_config mte_config = {
> + .sublists = {
> + BASE_SUBLIST,
> + VREGS_SUBLIST,
> + MTE_SUBLIST,
> + {0},
> + },
> +};
>
> static struct vcpu_config *vcpu_configs[] = {
> &vregs_config,
> @@ -1131,5 +1163,6 @@ static struct vcpu_config *vcpu_configs[] = {
> &sve_pmu_config,
> &pauth_config,
> &pauth_pmu_config,
> + &mte_config,
> };
> static int vcpu_configs_n = ARRAY_SIZE(vcpu_configs);
>
Is there any reason why we sidestep the combinations of MTE with PAuth
and PMU? I know this leads to an exponential set growth, but this is
the very purpose of this test, and we found bugs related to this in
the past.
A good first step would be to be able to build these combinations
dynamically, and only then add new sublists to the mix.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.