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Mon, 06 Jul 2026 10:54:33 -0700 (PDT) Date: Mon, 6 Jul 2026 18:54:07 +0100 In-Reply-To: <20260706175415.2604046-1-vdonnefort@google.com> Mime-Version: 1.0 References: <20260706175415.2604046-1-vdonnefort@google.com> X-Mailer: git-send-email 2.55.0.rc2.803.g1fd1e6609c-goog Message-ID: <20260706175415.2604046-11-vdonnefort@google.com> Subject: [PATCH v2 10/18] KVM: arm64: Add selftests for the pKVM heap allocator From: Vincent Donnefort To: maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kernel-team@android.com, qperret@google.com, tabba@google.com, Vincent Donnefort Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260706_185436_741148_0B1C48A0 X-CRM114-Status: GOOD ( 17.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Introduce a comprehensive runtime selftest for the pKVM hypervisor heap allocator, executed during init when CONFIG_NVHE_EL2_DEBUG is enabled. The selftest runs entirely at EL2 and exercises allocator's core mechanisms: * over-sized allocations * basic allocation and alignment * chunk recycling, splitting, merging * memory reclaiming * memory topup Signed-off-by: Vincent Donnefort diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index b427ef790b15..07a46860c8b2 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -117,6 +117,7 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___pkvm_hyp_topup, __KVM_HOST_SMCCC_FUNC___pkvm_hyp_reclaim, __KVM_HOST_SMCCC_FUNC___pkvm_hyp_reclaimable, + __KVM_HOST_SMCCC_FUNC___pkvm_hyp_alloc_selftest, MARKER(__KVM_HOST_SMCCC_FUNC_MAX) }; diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h index 3a8590d1793e..5837c2d7928a 100644 --- a/arch/arm64/include/asm/kvm_pkvm.h +++ b/arch/arm64/include/asm/kvm_pkvm.h @@ -19,6 +19,7 @@ enum pkvm_topup_id { PKVM_TOPUP_HYP_ALLOC, + PKVM_TOPUP_HYP_ALLOC_SELFTEST, }; unsigned long pkvm_hyp_reclaim(enum pkvm_topup_id id, unsigned long target); @@ -209,6 +210,7 @@ struct pkvm_mapping { enum pkvm_hyp_req_type { PKVM_HYP_NO_REQ = 0, PKVM_HYP_REQ_HYP_ALLOC, + PKVM_HYP_REQ_HYP_ALLOC_SELFTEST, __PKVM_HYP_REQ_TYPE_MAX, }; @@ -236,6 +238,7 @@ static inline size_t pkvm_hyp_req_arg_size(u8 type) case PKVM_HYP_NO_REQ: return 0; case PKVM_HYP_REQ_HYP_ALLOC: + case PKVM_HYP_REQ_HYP_ALLOC_SELFTEST: return sizeof(req->mem); default: WARN_ON(1); diff --git a/arch/arm64/kvm/hyp/include/nvhe/alloc.h b/arch/arm64/kvm/hyp/include/nvhe/alloc.h index 8f87a63f8946..329250dad6f6 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/alloc.h +++ b/arch/arm64/kvm/hyp/include/nvhe/alloc.h @@ -14,4 +14,11 @@ int hyp_alloc_init(size_t size); int hyp_alloc_topup(struct kvm_hyp_memcache *host_mc); unsigned long hyp_alloc_reclaimable(void); void hyp_alloc_reclaim(struct kvm_hyp_memcache *host_mc, unsigned long target); + +#ifdef CONFIG_NVHE_EL2_DEBUG +int hyp_allocator_selftest(void); +u32 hyp_alloc_selftest_topup_needed(void); +int hyp_alloc_selftest_topup(struct kvm_hyp_memcache *host_mc); +void hyp_alloc_selftest_reclaim(struct kvm_hyp_memcache *host_mc, unsigned long target); +#endif #endif diff --git a/arch/arm64/kvm/hyp/nvhe/alloc.c b/arch/arm64/kvm/hyp/nvhe/alloc.c index 07ef0a13855f..e7114dde9142 100644 --- a/arch/arm64/kvm/hyp/nvhe/alloc.c +++ b/arch/arm64/kvm/hyp/nvhe/alloc.c @@ -1007,9 +1007,17 @@ int hyp_alloc_errno(void) return hyp_allocator_errno(&hyp_allocator); } +static int selftest_init(void); + int hyp_alloc_init(size_t size) { - return hyp_allocator_init(&hyp_allocator, size); + int ret; + + ret = hyp_allocator_init(&hyp_allocator, size); + if (ret) + return ret; + + return selftest_init(); } void hyp_alloc_reclaim(struct kvm_hyp_memcache *mc, unsigned long target) @@ -1031,3 +1039,179 @@ u32 hyp_alloc_topup_needed(void) { return hyp_allocator_topup_needed(&hyp_allocator); } + +#ifdef CONFIG_NVHE_EL2_DEBUG +#define SELFTEST_MAX_PAGES 6 +#define SELFTEST_MAX_SIZE (PAGE_SIZE * SELFTEST_MAX_PAGES) + +static DEFINE_PER_CPU(int, __selftest_errno); +static DEFINE_PER_CPU(u32, __selftest_topup_needed); + +static struct hyp_allocator selftest_allocator = { + .errno = &__selftest_errno, + .topup_needed = &__selftest_topup_needed, + .lock = __HYP_SPIN_LOCK_UNLOCKED, +}; + +int hyp_alloc_selftest_topup(struct kvm_hyp_memcache *host_mc) +{ + return hyp_allocator_topup(&selftest_allocator, host_mc); +} + +void hyp_alloc_selftest_reclaim(struct kvm_hyp_memcache *host_mc, unsigned long target) +{ + hyp_allocator_reclaim(&selftest_allocator, host_mc, target); +} + +u32 hyp_alloc_selftest_topup_needed(void) +{ + return hyp_allocator_topup_needed(&selftest_allocator); +} + +static int selftest_init(void) +{ + return hyp_allocator_init(&selftest_allocator, SELFTEST_MAX_SIZE); +} + +static void *selftest_alloc(size_t size) +{ + return hyp_allocator_alloc(&selftest_allocator, size); +} + +static void selftest_free(void *addr) +{ + hyp_allocator_free(&selftest_allocator, addr); +} + +static int selftest_errno(void) +{ + return hyp_allocator_errno(&selftest_allocator); +} + +int hyp_allocator_selftest(void) +{ + struct hyp_allocator *allocator = &selftest_allocator; + static DEFINE_HYP_SPINLOCK(selftest_lock); + struct kvm_hyp_memcache host_mc = { }; + void *addr1, *addr2, *addr3, *addr4; + int ret; + + guard(hyp_spinlock)(&selftest_lock); + + if (allocator->mc.nr_pages < SELFTEST_MAX_PAGES) { + *this_cpu_ptr(allocator->topup_needed) = SELFTEST_MAX_PAGES - + allocator->mc.nr_pages; + return -ENOMEM; + } + + selftest_alloc(SELFTEST_MAX_SIZE); + if (selftest_errno() != -E2BIG) + return -EINVAL; + + selftest_alloc(SIZE_MAX); + if (selftest_errno() != -E2BIG) + return -EINVAL; + + /* Test first chunk */ + addr1 = selftest_alloc(0); + if (!addr1 || addr1 != (void *)allocator->start + chunk_hdr_size()) + return -EINVAL; + + /* Test second contiguous chunk with unaligned size */ + addr2 = selftest_alloc(MIN_ALLOC_SIZE + 1); + if (!addr2) + return -EINVAL; + addr3 = selftest_alloc(0); + if (!addr3 || + addr3 != addr2 + (2 * MIN_ALLOC_SIZE) + chunk_hdr_size()) + return -EINVAL; + + selftest_free(addr3); + + /* Test chunk recycling */ + selftest_free(addr1); + if (addr1 != selftest_alloc(0)) + return -EINVAL; + + /* Test chunk forward merging */ + addr3 = selftest_alloc(0); + selftest_free(addr2); + selftest_free(addr1); + if (addr1 != selftest_alloc(MIN_ALLOC_SIZE * 2)) + return -EINVAL; + + selftest_free(addr1); + + /* Test chunk splitting */ + if (addr1 != selftest_alloc(0)) + return -EINVAL; + if (addr2 != selftest_alloc(0)) + return -EINVAL; + + /* Test chunk backward merging */ + selftest_free(addr1); + selftest_free(addr2); + if (addr1 != selftest_alloc(MIN_ALLOC_SIZE * 2)) + return -EINVAL; + + selftest_free(addr1); + + /* Test chunk 3-way merging */ + addr1 = selftest_alloc(0); + addr2 = selftest_alloc(0); + addr4 = selftest_alloc(0); + selftest_free(addr1); + selftest_free(addr3); + selftest_free(addr2); + if (addr1 != selftest_alloc(MIN_ALLOC_SIZE * 3)) + return -EINVAL; + + selftest_free(addr4); + selftest_free(addr1); + + /* Test reclaiming */ + if (addr1 != selftest_alloc(0)) + return -EINVAL; + if (addr2 != selftest_alloc(PAGE_SIZE * 2)) + return -EINVAL; + addr3 = selftest_alloc(0); + addr4 = selftest_alloc(PAGE_SIZE); + + /* Test reclaiming the last chunk of the list */ + selftest_free(addr4); + hyp_allocator_reclaim(allocator, &host_mc, SELFTEST_MAX_PAGES); + if (host_mc.nr_pages != SELFTEST_MAX_PAGES - 3) + return -EINVAL; + + /* Test punching a hole in the middle of a free chunk ... */ + selftest_free(addr2); + hyp_allocator_reclaim(allocator, &host_mc, SELFTEST_MAX_PAGES); + if (host_mc.nr_pages != SELFTEST_MAX_PAGES - 2) + return -EINVAL; + + if (selftest_alloc(PAGE_SIZE)) + return -EINVAL; + if (selftest_errno() != -ENOMEM) + return -EINVAL; + + /* ... and to refill this hole */ + ret = hyp_allocator_topup(allocator, &host_mc); + if (ret) + return ret; + /* Chunk at addr2 was made smaller by the reclaim */ + if (addr2 != selftest_alloc(PAGE_SIZE)) + return -EINVAL; + + /* Test reclaiming the entire allocator from the host */ + selftest_free(addr3); + selftest_free(addr2); + selftest_free(addr1); + if (addr1 != selftest_alloc(SELFTEST_MAX_PAGES * PAGE_SIZE - chunk_hdr_size())) + return -EINVAL; + selftest_free(addr1); + + return 0; +} +#else +static int selftest_init(void) { return 0; } +#endif diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 8fbebe64a93d..105313bb3dd9 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -633,6 +633,28 @@ static void handle___pkvm_finalize_teardown_vm(struct kvm_cpu_context *host_ctxt cpu_reg(host_ctxt, 1) = __pkvm_finalize_teardown_vm(handle); } +#ifdef CONFIG_NVHE_EL2_DEBUG +static void handle___pkvm_hyp_alloc_selftest(struct kvm_cpu_context *host_ctxt) +{ + struct pkvm_hyp_req req = { .type = PKVM_HYP_NO_REQ }; + int ret; + + ret = hyp_allocator_selftest(); + if (ret == -ENOMEM) { + req.type = PKVM_HYP_REQ_HYP_ALLOC_SELFTEST; + req.mem.nr_pages = hyp_alloc_selftest_topup_needed(); + } + + cpu_reg(host_ctxt, 1) = ret; + pkvm_hyp_req_to_smccc(host_ctxt, &req); +} +#else +static void handle___pkvm_hyp_alloc_selftest(struct kvm_cpu_context *host_ctxt) +{ + cpu_reg(host_ctxt, 1) = -EPERM; +} +#endif + static void handle___pkvm_hyp_topup(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(enum pkvm_topup_id, id, host_ctxt, 1); @@ -648,6 +670,11 @@ static void handle___pkvm_hyp_topup(struct kvm_cpu_context *host_ctxt) case PKVM_TOPUP_HYP_ALLOC: ret = hyp_alloc_topup(&host_mc); break; +#ifdef CONFIG_NVHE_EL2_DEBUG + case PKVM_TOPUP_HYP_ALLOC_SELFTEST: + ret = hyp_alloc_selftest_topup(&host_mc); + break; +#endif default: ret = -EINVAL; } @@ -668,6 +695,11 @@ static void handle___pkvm_hyp_reclaim(struct kvm_cpu_context *host_ctxt) case PKVM_TOPUP_HYP_ALLOC: hyp_alloc_reclaim(&host_mc, target); break; +#ifdef CONFIG_NVHE_EL2_DEBUG + case PKVM_TOPUP_HYP_ALLOC_SELFTEST: + hyp_alloc_selftest_reclaim(&host_mc, target); + break; +#endif default: ret = -EINVAL; } @@ -826,6 +858,7 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__pkvm_hyp_topup), HANDLE_FUNC(__pkvm_hyp_reclaim), HANDLE_FUNC(__pkvm_hyp_reclaimable), + HANDLE_FUNC(__pkvm_hyp_alloc_selftest), }; static void handle_host_hcall(struct kvm_cpu_context *host_ctxt) diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index eb4c60a0db5a..f7e1846d6093 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -137,6 +137,7 @@ unsigned long pkvm_hyp_reclaimable(enum pkvm_topup_id id) { return kvm_call_hyp_nvhe(__pkvm_hyp_reclaimable, id); } + static void __pkvm_destroy_hyp_vm(struct kvm *kvm) { if (pkvm_hyp_vm_is_created(kvm)) { @@ -325,6 +326,22 @@ static int __init pkvm_drop_host_privileges(void) return ret; } +static void __init pkvm_selftests(void) +{ +#ifdef CONFIG_NVHE_EL2_DEBUG + int ret = pkvm_call_hyp_req(__pkvm_hyp_alloc_selftest); + unsigned long reclaimed; + + reclaimed = pkvm_hyp_reclaim(PKVM_TOPUP_HYP_ALLOC_SELFTEST, ULONG_MAX); + + /* On failure, not all the pages may be reclaimable */ + if (!ret) + WARN_ON(reclaimed != 6 /* SELFTEST_MAX_PAGES */); + else + kvm_err("pKVM hyp allocator selftest failed (%d)\n", ret); +#endif +} + static int __init finalize_pkvm(void) { int ret; @@ -345,6 +362,9 @@ static int __init finalize_pkvm(void) if (ret) pr_err("Failed to finalize Hyp protection: %d\n", ret); + if (!ret) + pkvm_selftests(); + return ret; } device_initcall_sync(finalize_pkvm); @@ -651,6 +671,9 @@ static int pkvm_handle_hyp_req(struct pkvm_hyp_req *req) case PKVM_HYP_REQ_HYP_ALLOC: ret = pkvm_hyp_topup(PKVM_TOPUP_HYP_ALLOC, req->mem.nr_pages); break; + case PKVM_HYP_REQ_HYP_ALLOC_SELFTEST: + ret = pkvm_hyp_topup(PKVM_TOPUP_HYP_ALLOC_SELFTEST, req->mem.nr_pages); + break; } trace_kvm_handle_pkvm_hyp_req(req, ret); -- 2.55.0.rc2.803.g1fd1e6609c-goog