From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C910A2D3750 for ; Mon, 24 Nov 2025 19:02:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764010922; cv=none; b=FbX0+ccQUrUgylmXZdZDxE28BheGAP9yUG1m9zDQlFiRM464kv3FAgvBdzvCvySusrUgyxV9LGVUKegVHV/UKqX2FnFT1agu3fmpTQcPj5lPuhch05G6wLNUEbn2tC+ZIiZUI5apIUYBVLLsuLu7FDv9oESU4KG7D4qTcmiP5p4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764010922; c=relaxed/simple; bh=qlNCPFPZ5sK3tkOJkWN2mmTRvbJFKCInbVuD79GxMtY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hGwTK4PAHnVzcYGygO9/3HOCSjE8CpPieMn/Tbf698gx4u5TfwxHOEfhWrgvIjhAk7BnHoej+Gfa8IAyFoJpbSDtTVIGse3+xvIRxS6VgyfaYuk4A0TCuZW3FFaAh4zLCwVcIt3nhlkX4hXA2Xyc7pMhFUT/O3niou7SwpOxQlQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=az8TGlUU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="az8TGlUU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A0DAC4AF09; Mon, 24 Nov 2025 19:02:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764010922; bh=qlNCPFPZ5sK3tkOJkWN2mmTRvbJFKCInbVuD79GxMtY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=az8TGlUUzNeAchqi9PBRUKrSqdqT/I8/5pDilNmVN/Cw+67Lj44g+MAL4HblyvrB5 bkqGIJUVDCzBy92dDmRxj49pVEQRCOGbWhuJKp8TlNv/lm68wUZffjkQl54jg0EhoT Ds43NEUMXPXv+RKSFbIjP4CtWTyJZfRevZ9B7zxZljKw13Q/s9EBp37QqGSSpHefyf NUyB/aZTY3GdhtFrU0/ElZ2xPdpQH5sBD79plgvDoEjaZ9fD5De5YVITxkdAOuLGsC 4pVKZtsPaIiR+7UKgeJ1i+4HGmzvxgW8gdwrlDO0oJI/i6Pw7CndheRFs3ih623o3z o4Ei+jWbKSQwA== From: Oliver Upton To: kvmarm@lists.linux.dev Cc: Marc Zyngier , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Oliver Upton Subject: [PATCH v3 15/15] KVM: arm64: selftests: Add test for AT emulation Date: Mon, 24 Nov 2025 11:01:57 -0800 Message-ID: <20251124190158.177318-16-oupton@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251124190158.177318-1-oupton@kernel.org> References: <20251124190158.177318-1-oupton@kernel.org> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add a basic test for AT emulation in the EL2&0 and EL1&0 translation regimes. Signed-off-by: Oliver Upton --- tools/testing/selftests/kvm/Makefile.kvm | 1 + tools/testing/selftests/kvm/arm64/at.c | 166 ++++++++++++++++++ .../testing/selftests/kvm/include/kvm_util.h | 1 + tools/testing/selftests/kvm/lib/kvm_util.c | 10 ++ 4 files changed, 178 insertions(+) create mode 100644 tools/testing/selftests/kvm/arm64/at.c diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm index 148d427ff24b..81b3aa54678a 100644 --- a/tools/testing/selftests/kvm/Makefile.kvm +++ b/tools/testing/selftests/kvm/Makefile.kvm @@ -156,6 +156,7 @@ TEST_GEN_PROGS_EXTENDED_x86 += x86/nx_huge_pages_test TEST_GEN_PROGS_arm64 = $(TEST_GEN_PROGS_COMMON) TEST_GEN_PROGS_arm64 += arm64/aarch32_id_regs TEST_GEN_PROGS_arm64 += arm64/arch_timer_edge_cases +TEST_GEN_PROGS_arm64 += arm64/at TEST_GEN_PROGS_arm64 += arm64/debug-exceptions TEST_GEN_PROGS_arm64 += arm64/hello_el2 TEST_GEN_PROGS_arm64 += arm64/host_sve diff --git a/tools/testing/selftests/kvm/arm64/at.c b/tools/testing/selftests/kvm/arm64/at.c new file mode 100644 index 000000000000..acecb6ab5071 --- /dev/null +++ b/tools/testing/selftests/kvm/arm64/at.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * at - Test for KVM's AT emulation in the EL2&0 and EL1&0 translation regimes. + */ +#include "kvm_util.h" +#include "processor.h" +#include "test_util.h" +#include "ucall.h" + +#include + +#define TEST_ADDR 0x80000000 + +enum { + CLEAR_ACCESS_FLAG, + TEST_ACCESS_FLAG, +}; + +static u64 *ptep_hva; + +#define copy_el2_to_el1(reg) \ + write_sysreg_s(read_sysreg_s(SYS_##reg##_EL1), SYS_##reg##_EL12) + +/* Yes, this is an ugly hack */ +#define __at(op, addr) write_sysreg_s(addr, op) + +#define test_at_insn(op, expect_fault) \ +do { \ + u64 par, fsc; \ + bool fault; \ + \ + GUEST_SYNC(CLEAR_ACCESS_FLAG); \ + \ + __at(OP_AT_##op, TEST_ADDR); \ + isb(); \ + par = read_sysreg(par_el1); \ + \ + fault = par & SYS_PAR_EL1_F; \ + fsc = FIELD_GET(SYS_PAR_EL1_FST, par); \ + \ + __GUEST_ASSERT((expect_fault) == fault, \ + "AT "#op": %sexpected fault (par: %lx)1", \ + (expect_fault) ? "" : "un", par); \ + if ((expect_fault)) { \ + __GUEST_ASSERT(fsc == ESR_ELx_FSC_ACCESS_L(3), \ + "AT "#op": expected access flag fault (par: %lx)", \ + par); \ + } else { \ + GUEST_ASSERT_EQ(FIELD_GET(SYS_PAR_EL1_ATTR, par), MAIR_ATTR_NORMAL); \ + GUEST_ASSERT_EQ(FIELD_GET(SYS_PAR_EL1_SH, par), PTE_SHARED >> 8); \ + GUEST_ASSERT_EQ(par & SYS_PAR_EL1_PA, TEST_ADDR); \ + GUEST_SYNC(TEST_ACCESS_FLAG); \ + } \ +} while (0) + +static void test_at(bool expect_fault) +{ + test_at_insn(S1E2R, expect_fault); + test_at_insn(S1E2W, expect_fault); + + /* Reuse the stage-1 MMU context from EL2 at EL1 */ + copy_el2_to_el1(SCTLR); + copy_el2_to_el1(MAIR); + copy_el2_to_el1(TCR); + copy_el2_to_el1(TTBR0); + copy_el2_to_el1(TTBR1); + + /* Disable stage-2 translation and enter a non-host context */ + write_sysreg(0, vtcr_el2); + write_sysreg(0, vttbr_el2); + sysreg_clear_set(hcr_el2, HCR_EL2_TGE | HCR_EL2_VM, 0); + isb(); + + test_at_insn(S1E1R, expect_fault); + test_at_insn(S1E1W, expect_fault); +} + +static void guest_code(void) +{ + sysreg_clear_set(tcr_el1, TCR_HA, 0); + isb(); + + test_at(true); + + if (!SYS_FIELD_GET(ID_AA64MMFR1_EL1, HAFDBS, read_sysreg(id_aa64mmfr1_el1))) + GUEST_DONE(); + + /* + * KVM's software PTW makes the implementation choice that the AT + * instruction sets the access flag. + */ + sysreg_clear_set(tcr_el1, 0, TCR_HA); + isb(); + test_at(false); + + GUEST_DONE(); +} + +static void handle_sync(struct kvm_vcpu *vcpu, struct ucall *uc) +{ + switch (uc->args[1]) { + case CLEAR_ACCESS_FLAG: + /* + * Delete + reinstall the memslot to invalidate stage-2 + * mappings of the stage-1 page tables, forcing KVM to + * use the 'slow' AT emulation path. + * + * This and clearing the access flag from host userspace + * ensures that the access flag cannot be set speculatively + * and is reliably cleared at the time of the AT instruction. + */ + clear_bit(__ffs(PTE_AF), ptep_hva); + vm_mem_region_reload(vcpu->vm, vcpu->vm->memslots[MEM_REGION_PT]); + break; + case TEST_ACCESS_FLAG: + TEST_ASSERT(test_bit(__ffs(PTE_AF), ptep_hva), + "Expected access flag to be set (desc: %lu)", *ptep_hva); + break; + default: + TEST_FAIL("Unexpected SYNC arg: %lu", uc->args[1]); + } +} + +static void run_test(struct kvm_vcpu *vcpu) +{ + struct ucall uc; + + while (true) { + vcpu_run(vcpu); + switch (get_ucall(vcpu, &uc)) { + case UCALL_DONE: + return; + case UCALL_SYNC: + handle_sync(vcpu, &uc); + continue; + case UCALL_ABORT: + REPORT_GUEST_ASSERT(uc); + return; + default: + TEST_FAIL("Unexpeced ucall: %lu", uc.cmd); + } + } +} + +int main(void) +{ + struct kvm_vcpu_init init; + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + + TEST_REQUIRE(kvm_check_cap(KVM_CAP_ARM_EL2)); + + vm = vm_create(1); + + kvm_get_default_vcpu_target(vm, &init); + init.features[0] |= BIT(KVM_ARM_VCPU_HAS_EL2); + vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code); + kvm_arch_vm_finalize_vcpus(vm); + + virt_map(vm, TEST_ADDR, TEST_ADDR, 1); + ptep_hva = virt_get_pte_hva_at_level(vm, TEST_ADDR, 3); + run_test(vcpu); + + kvm_vm_free(vm); + return 0; +} diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h index d3f3e455c031..41467dad9178 100644 --- a/tools/testing/selftests/kvm/include/kvm_util.h +++ b/tools/testing/selftests/kvm/include/kvm_util.h @@ -715,6 +715,7 @@ static inline bool vm_arch_has_protected_memory(struct kvm_vm *vm) #endif void vm_mem_region_set_flags(struct kvm_vm *vm, uint32_t slot, uint32_t flags); +void vm_mem_region_reload(struct kvm_vm *vm, uint32_t slot); void vm_mem_region_move(struct kvm_vm *vm, uint32_t slot, uint64_t new_gpa); void vm_mem_region_delete(struct kvm_vm *vm, uint32_t slot); struct kvm_vcpu *__vm_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id); diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 1a93d6361671..d6538bb17740 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -1201,6 +1201,16 @@ void vm_mem_region_set_flags(struct kvm_vm *vm, uint32_t slot, uint32_t flags) ret, errno, slot, flags); } +void vm_mem_region_reload(struct kvm_vm *vm, uint32_t slot) +{ + struct userspace_mem_region *region = memslot2region(vm, slot); + struct kvm_userspace_memory_region2 tmp = region->region; + + tmp.memory_size = 0; + vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION2, &tmp); + vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION2, ®ion->region); +} + /* * VM Memory Region Move * -- 2.47.3