From: Kalesh Singh <kaleshsingh@google.com>
To: unlisted-recipients:; (no To-header on input)
Cc: 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>,
Mark Rutland <mark.rutland@arm.com>,
Mark Brown <broonie@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Peter Collingbourne <pcc@google.com>,
"Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>,
Stephen Boyd <swboyd@chromium.org>,
Andrew Walbran <qwandor@google.com>,
Andrew Scull <ascull@google.com>,
Ard Biesheuvel <ardb@kernel.org>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org
Subject: [PATCH v5 6/8] KVM: arm64: Add hypervisor overflow stack
Date: Mon, 7 Mar 2022 10:49:04 -0800 [thread overview]
Message-ID: <20220307184935.1704614-7-kaleshsingh@google.com> (raw)
In-Reply-To: <20220307184935.1704614-1-kaleshsingh@google.com>
Allocate and switch to 16-byte aligned secondary stack on overflow. This
provides us stack space to better handle overflows; and is used in
a subsequent patch to dump the hypervisor stacktrace. The overflow stack
is only allocated if CONFIG_NVHE_EL2_DEBUG is enabled, as hypervisor
stacktraces is a debug feature dependent on CONFIG_NVHE_EL2_DEBUG.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
---
Changes in v4:
- Update comment to clarify resetting the SP to the top of the stack
only happens if CONFIG_NVHE_EL2_DEBUG is disabled, per Fuad
arch/arm64/kvm/hyp/nvhe/host.S | 11 ++++++++---
arch/arm64/kvm/hyp/nvhe/switch.c | 5 +++++
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S
index be6d844279b1..a0c4b4f1549f 100644
--- a/arch/arm64/kvm/hyp/nvhe/host.S
+++ b/arch/arm64/kvm/hyp/nvhe/host.S
@@ -179,13 +179,18 @@ SYM_FUNC_END(__host_hvc)
b hyp_panic
.L__hyp_sp_overflow\@:
+#ifdef CONFIG_NVHE_EL2_DEBUG
+ /* Switch to the overflow stack */
+ adr_this_cpu sp, hyp_overflow_stack + PAGE_SIZE, x0
+#else
/*
- * Reset SP to the top of the stack, to allow handling the hyp_panic.
- * This corrupts the stack but is ok, since we won't be attempting
- * any unwinding here.
+ * If !CONFIG_NVHE_EL2_DEBUG, reset SP to the top of the stack, to
+ * allow handling the hyp_panic. This corrupts the stack but is ok,
+ * since we won't be attempting any unwinding here.
*/
ldr_this_cpu x0, kvm_init_params + NVHE_INIT_STACK_HYP_VA, x1
mov sp, x0
+#endif
bl hyp_panic_bad_stack
ASM_BUG()
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 703a5d3f611b..efc20273a352 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -34,6 +34,11 @@ DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);
DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
DEFINE_PER_CPU(unsigned long, kvm_hyp_vector);
+#ifdef CONFIG_NVHE_EL2_DEBUG
+DEFINE_PER_CPU(unsigned long [PAGE_SIZE/sizeof(long)], hyp_overflow_stack)
+ __aligned(16);
+#endif
+
static void __activate_traps(struct kvm_vcpu *vcpu)
{
u64 val;
--
2.35.1.616.g0bdcbb4464-goog
next prev parent reply other threads:[~2022-03-07 18:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-07 18:48 [PATCH v5 0/8] KVM: arm64: Hypervisor stack enhancements Kalesh Singh
2022-03-07 18:48 ` [PATCH v5 1/8] KVM: arm64: Introduce hyp_alloc_private_va_range() Kalesh Singh
2022-03-08 20:21 ` Stephen Boyd
2022-03-08 23:09 ` Kalesh Singh
2022-03-09 16:50 ` Quentin Perret
2022-03-09 17:04 ` Kalesh Singh
2022-03-07 18:49 ` [PATCH v5 2/8] KVM: arm64: Introduce pkvm_alloc_private_va_range() Kalesh Singh
2022-03-07 18:49 ` [PATCH v5 3/8] KVM: arm64: Add guard pages for KVM nVHE hypervisor stack Kalesh Singh
2022-03-07 18:49 ` [PATCH v5 4/8] KVM: arm64: Add guard pages for pKVM (protected nVHE) " Kalesh Singh
2022-03-07 18:49 ` [PATCH v5 5/8] KVM: arm64: Detect and handle hypervisor stack overflows Kalesh Singh
2022-03-07 18:49 ` Kalesh Singh [this message]
2022-03-07 18:49 ` [PATCH v5 7/8] KVM: arm64: Unwind and dump nVHE HYP stacktrace Kalesh Singh
2022-03-07 18:49 ` [PATCH v5 8/8] KVM: arm64: Symbolize the nVHE HYP backtrace Kalesh Singh
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