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From: Kalesh Singh <kaleshsingh@google.com>
To: maz@kernel.org, mark.rutland@arm.com, broonie@kernel.org,
	 madvenka@linux.microsoft.com, tabba@google.com
Cc: will@kernel.org, qperret@google.com, kaleshsingh@google.com,
	 james.morse@arm.com, alexandru.elisei@arm.com,
	suzuki.poulose@arm.com,  catalin.marinas@arm.com,
	andreyknvl@gmail.com, vincenzo.frascino@arm.com,
	 mhiramat@kernel.org, ast@kernel.org, drjones@redhat.com,
	 wangkefeng.wang@huawei.com, elver@google.com, keirf@google.com,
	 yuzenghui@huawei.com, ardb@kernel.org, oupton@google.com,
	 linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu,  linux-kernel@vger.kernel.org,
	android-mm@google.com, kernel-team@android.com
Subject: [PATCH v5 09/17] KVM: arm64: Allocate shared pKVM hyp stacktrace buffers
Date: Wed, 20 Jul 2022 22:57:20 -0700	[thread overview]
Message-ID: <20220721055728.718573-10-kaleshsingh@google.com> (raw)
In-Reply-To: <20220721055728.718573-1-kaleshsingh@google.com>

In protected nVHE mode the host cannot directly access
hypervisor memory, so we will dump the hypervisor stacktrace
to a shared buffer with the host.

The minimum size for the buffer required, assuming the min frame
size of [x29, x30] (2 * sizeof(long)), is half the combined size of
the hypervisor and overflow stacks plus an additional entry to
delimit the end of the stacktrace.

The stacktrace buffers are used later in the seried to dump the
nVHE hypervisor stacktrace when using protected-mode.

Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
---

Changes in v5:
  - Fix typo in commit text, per Marc

 arch/arm64/include/asm/memory.h      | 8 ++++++++
 arch/arm64/kvm/hyp/nvhe/stacktrace.c | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 0af70d9abede..cab80a9a4086 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -113,6 +113,14 @@
 
 #define OVERFLOW_STACK_SIZE	SZ_4K
 
+/*
+ * With the minimum frame size of [x29, x30], exactly half the combined
+ * sizes of the hyp and overflow stacks is the maximum size needed to
+ * save the unwinded stacktrace; plus an additional entry to delimit the
+ * end.
+ */
+#define NVHE_STACKTRACE_SIZE	((OVERFLOW_STACK_SIZE + PAGE_SIZE) / 2 + sizeof(long))
+
 /*
  * Alignment of kernel segments (e.g. .text, .data).
  *
diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe/stacktrace.c
index a3d5b34e1249..69e65b457f1c 100644
--- a/arch/arm64/kvm/hyp/nvhe/stacktrace.c
+++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c
@@ -9,3 +9,7 @@
 
 DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack)
 	__aligned(16);
+
+#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE
+DEFINE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)], pkvm_stacktrace);
+#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */
-- 
2.37.0.170.g444d1eabd0-goog


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  parent reply	other threads:[~2022-07-21  6:02 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-21  5:57 [PATCH v5 00/17] KVM nVHE Hypervisor stack unwinder Kalesh Singh
2022-07-21  5:57 ` [PATCH v5 01/17] arm64: stacktrace: Add shared header for common stack unwinding code Kalesh Singh
2022-07-21  5:57 ` [PATCH v5 02/17] arm64: stacktrace: Factor out on_accessible_stack_common() Kalesh Singh
2022-07-21  5:57 ` [PATCH v5 03/17] arm64: stacktrace: Factor out unwind_next_common() Kalesh Singh
2022-07-21  5:57 ` [PATCH v5 04/17] arm64: stacktrace: Handle frame pointer from different address spaces Kalesh Singh
2022-07-21  9:57   ` Fuad Tabba
2022-07-21  5:57 ` [PATCH v5 05/17] arm64: stacktrace: Factor out common unwind() Kalesh Singh
2022-07-25 14:05   ` Mark Brown
2022-07-21  5:57 ` [PATCH v5 06/17] arm64: stacktrace: Add description of stacktrace/common.h Kalesh Singh
2022-07-21  9:57   ` Fuad Tabba
2022-07-21  5:57 ` [PATCH v5 07/17] KVM: arm64: On stack overflow switch to hyp overflow_stack Kalesh Singh
2022-07-21  5:57 ` [PATCH v5 08/17] KVM: arm64: Add PROTECTED_NVHE_STACKTRACE Kconfig Kalesh Singh
2022-07-21  9:57   ` Fuad Tabba
2022-07-21  5:57 ` Kalesh Singh [this message]
2022-07-21  9:57   ` [PATCH v5 09/17] KVM: arm64: Allocate shared pKVM hyp stacktrace buffers Fuad Tabba
2022-07-21  5:57 ` [PATCH v5 10/17] KVM: arm64: Stub implementation of pKVM HYP stack unwinder Kalesh Singh
2022-07-21  9:58   ` Fuad Tabba
2022-07-21  5:57 ` [PATCH v5 11/17] KVM: arm64: Stub implementation of non-protected nVHE " Kalesh Singh
2022-07-21  9:58   ` Fuad Tabba
2022-07-21  5:57 ` [PATCH v5 12/17] KVM: arm64: Save protected-nVHE (pKVM) hyp stacktrace Kalesh Singh
2022-07-21  9:58   ` Fuad Tabba
2022-07-22 15:33   ` Oliver Upton
2022-07-22 17:28     ` Kalesh Singh
2022-07-21  5:57 ` [PATCH v5 13/17] KVM: arm64: Prepare non-protected nVHE hypervisor stacktrace Kalesh Singh
2022-07-21  9:58   ` Fuad Tabba
2022-07-21  5:57 ` [PATCH v5 14/17] KVM: arm64: Implement protected nVHE hyp stack unwinder Kalesh Singh
2022-07-21  9:58   ` Fuad Tabba
2022-07-21  5:57 ` [PATCH v5 15/17] KVM: arm64: Implement non-protected " Kalesh Singh
2022-07-21  9:58   ` Fuad Tabba
2022-07-21  5:57 ` [PATCH v5 16/17] KVM: arm64: Introduce pkvm_dump_backtrace() Kalesh Singh
2022-07-21  9:59   ` Fuad Tabba
2022-07-22 11:16   ` Oliver Upton
2022-07-22 17:25     ` Kalesh Singh
2022-07-21  5:57 ` [PATCH v5 17/17] KVM: arm64: Introduce hyp_dump_backtrace() Kalesh Singh
2022-07-21  9:59   ` Fuad Tabba
2022-07-21 20:35   ` Oliver Upton
2022-07-22  0:01     ` Kalesh Singh
2022-07-21  9:55 ` [PATCH v5 00/17] KVM nVHE Hypervisor stack unwinder Fuad Tabba
2022-07-21 16:06   ` Kalesh Singh
2022-07-22 10:48 ` Oliver Upton

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