Re: [PATCH] KVM: selftests: Add coverage of MTE system registers

On Wed, 08 Mar 2023 17:12:26 +0000, Mark Brown broonie@kernel.org 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@kernel.org

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.