[PATCH v5 07/17] KVM: arm64: On stack overflow switch to hyp overflow_stack
From: Kalesh Singh <hidden>
Date: 2022-07-21 05:58:09
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
On hyp stack overflow switch to 16-byte aligned secondary stack. This provides us stack space to better handle overflows; and is used in a subsequent patch to dump the hypervisor stacktrace. Signed-off-by: Kalesh Singh <redacted> Reviewed-by: Fuad Tabba <redacted> --- Changes in v5: - Add Reviewed-by tag from Fuad arch/arm64/kvm/hyp/nvhe/Makefile | 2 +- arch/arm64/kvm/hyp/nvhe/host.S | 9 ++------- arch/arm64/kvm/hyp/nvhe/stacktrace.c | 11 +++++++++++ 3 files changed, 14 insertions(+), 8 deletions(-) create mode 100644 arch/arm64/kvm/hyp/nvhe/stacktrace.c
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index f9fe4dc21b1f..524e7dad5739 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile@@ -14,7 +14,7 @@ lib-objs := $(addprefix ../../../lib/, $(lib-objs)) obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \ hyp-main.o hyp-smp.o psci-relay.o early_alloc.o page_alloc.o \ - cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o + cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \ ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o obj-$(CONFIG_DEBUG_LIST) += list_debug.o
diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S
index ea6a397b64a6..b6c0188c4b35 100644
--- a/arch/arm64/kvm/hyp/nvhe/host.S
+++ b/arch/arm64/kvm/hyp/nvhe/host.S@@ -177,13 +177,8 @@ SYM_FUNC_END(__host_hvc) b hyp_panic .L__hyp_sp_overflow\@: - /* - * 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 + /* Switch to the overflow stack */ + adr_this_cpu sp, overflow_stack + OVERFLOW_STACK_SIZE, x0 b hyp_panic_bad_stack ASM_BUG()
diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe/stacktrace.c
new file mode 100644
index 000000000000..a3d5b34e1249
--- /dev/null
+++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c@@ -0,0 +1,11 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * KVM nVHE hypervisor stack tracing support. + * + * Copyright (C) 2022 Google LLC + */ +#include <asm/memory.h> +#include <asm/percpu.h> + +DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack) + __aligned(16);
--
2.37.0.170.g444d1eabd0-goog
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