From: Kalesh Singh <kaleshsingh@google.com>
To: unlisted-recipients:; (no To-header on input)
Cc: mark.rutland@arm.com, broonie@kernel.org, will@kernel.org,
maz@kernel.org, qperret@google.com, tabba@google.com,
surenb@google.com, kernel-team@android.com,
Kalesh Singh <kaleshsingh@google.com>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Peter Collingbourne <pcc@google.com>,
Alexei Starovoitov <ast@kernel.org>,
"Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>,
Andrew Jones <drjones@redhat.com>, Marco Elver <elver@google.com>,
Zenghui Yu <yuzenghui@huawei.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Keir Fraser <keirf@google.com>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org
Subject: [PATCH v2 4/5] KVM: arm64: Allocate shared stacktrace pages
Date: Mon, 2 May 2022 12:12:04 -0700 [thread overview]
Message-ID: <20220502191222.4192768-5-kaleshsingh@google.com> (raw)
In-Reply-To: <20220502191222.4192768-1-kaleshsingh@google.com>
The nVHE hypervisor can use this shared area to dump its stacktrace
addresses on hyp_panic(). Symbolization and printing the stacktrace can
then be handled by the host in EL1 (done in a later patch in this series).
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
---
arch/arm64/include/asm/kvm_asm.h | 1 +
arch/arm64/kvm/arm.c | 34 ++++++++++++++++++++++++++++++++
arch/arm64/kvm/hyp/nvhe/setup.c | 11 +++++++++++
3 files changed, 46 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 2e277f2ed671..ad31ac68264f 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -174,6 +174,7 @@ struct kvm_nvhe_init_params {
unsigned long hcr_el2;
unsigned long vttbr;
unsigned long vtcr;
+ unsigned long stacktrace_hyp_va;
};
/* Translate a kernel address @ptr into its equivalent linear mapping */
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index d300def44f5c..26005182da20 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -50,6 +50,7 @@ DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector);
static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
+DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stacktrace_page);
unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
@@ -1484,6 +1485,7 @@ static void cpu_prepare_hyp_mode(int cpu)
tcr |= (idmap_t0sz & GENMASK(TCR_TxSZ_WIDTH - 1, 0)) << TCR_T0SZ_OFFSET;
params->tcr_el2 = tcr;
+ params->stacktrace_hyp_va = kern_hyp_va(per_cpu(kvm_arm_hyp_stacktrace_page, cpu));
params->pgd_pa = kvm_mmu_get_httbr();
if (is_protected_kvm_enabled())
params->hcr_el2 = HCR_HOST_NVHE_PROTECTED_FLAGS;
@@ -1777,6 +1779,7 @@ static void teardown_hyp_mode(void)
free_hyp_pgds();
for_each_possible_cpu(cpu) {
free_page(per_cpu(kvm_arm_hyp_stack_page, cpu));
+ free_page(per_cpu(kvm_arm_hyp_stacktrace_page, cpu));
free_pages(kvm_arm_hyp_percpu_base[cpu], nvhe_percpu_order());
}
}
@@ -1868,6 +1871,23 @@ static int init_hyp_mode(void)
per_cpu(kvm_arm_hyp_stack_page, cpu) = stack_page;
}
+ /*
+ * Allocate stacktrace pages for Hypervisor-mode.
+ * This is used by the hypervisor to share its stacktrace
+ * with the host on a hyp_panic().
+ */
+ for_each_possible_cpu(cpu) {
+ unsigned long stacktrace_page;
+
+ stacktrace_page = __get_free_page(GFP_KERNEL);
+ if (!stacktrace_page) {
+ err = -ENOMEM;
+ goto out_err;
+ }
+
+ per_cpu(kvm_arm_hyp_stacktrace_page, cpu) = stacktrace_page;
+ }
+
/*
* Allocate and initialize pages for Hypervisor-mode percpu regions.
*/
@@ -1975,6 +1995,20 @@ static int init_hyp_mode(void)
params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE);
}
+ /*
+ * Map the hyp stacktrace pages.
+ */
+ for_each_possible_cpu(cpu) {
+ char *stacktrace_page = (char *)per_cpu(kvm_arm_hyp_stacktrace_page, cpu);
+
+ err = create_hyp_mappings(stacktrace_page, stacktrace_page + PAGE_SIZE,
+ PAGE_HYP);
+ if (err) {
+ kvm_err("Cannot map hyp stacktrace page\n");
+ goto out_err;
+ }
+ }
+
for_each_possible_cpu(cpu) {
char *percpu_begin = (char *)kvm_arm_hyp_percpu_base[cpu];
char *percpu_end = percpu_begin + nvhe_percpu_size();
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index e8d4ea2fcfa0..9b81bf2d40d7 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -135,6 +135,17 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
/* Update stack_hyp_va to end of the stack's private VA range */
params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE);
+
+ /*
+ * Map the stacktrace pages as shared and transfer ownership to
+ * the hypervisor.
+ */
+ prot = pkvm_mkstate(PAGE_HYP, PKVM_PAGE_SHARED_OWNED);
+ start = (void *)params->stacktrace_hyp_va;
+ end = start + PAGE_SIZE;
+ ret = pkvm_create_mappings(start, end, prot);
+ if (ret)
+ return ret;
}
/*
--
2.36.0.464.gb9c8b46e94-goog
next prev parent reply other threads:[~2022-05-02 19:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-02 19:12 [PATCH v2 0/5] KVM nVHE Hypervisor stack unwinder Kalesh Singh
2022-05-02 19:12 ` [PATCH v2 1/5] KVM: arm64: Factor out common stack unwinding logic Kalesh Singh
2022-05-04 13:41 ` Mark Brown
2022-05-02 19:12 ` [PATCH v2 2/5] KVM: arm64: Compile stacktrace.nvhe.o Kalesh Singh
2022-05-04 14:16 ` Mark Brown
2022-05-04 16:02 ` Kalesh Singh
2022-05-02 19:12 ` [PATCH v2 3/5] KVM: arm64: Add hypervisor overflow stack Kalesh Singh
2022-05-02 19:12 ` Kalesh Singh [this message]
2022-05-02 19:12 ` [PATCH v2 5/5] KVM: arm64: Unwind and dump nVHE hypervisor stacktrace Kalesh Singh
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