Commit 548ec333 authored by Kalesh Singh's avatar Kalesh Singh Committed by Marc Zyngier
Browse files

KVM: arm64: On stack overflow switch to hyp overflow_stack 



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: default avatarKalesh Singh <kaleshsingh@google.com>
Reviewed-by: default avatarFuad Tabba <tabba@google.com>
Tested-by: default avatarFuad Tabba <tabba@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-8-kaleshsingh@google.com
parent 051ece67

arch/arm64/kvm/hyp/nvhe/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/arm64/kvm/hyp/nvhe/host.S

+2 −7
Original line number Diff line number Diff line
@@ -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()

arch/arm64/kvm/hyp/nvhe/stacktrace.c

0 → 100644
+11 −0
Original line number Diff line number Diff line 
// 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);