[PATCH 1/2] KVM: arm64: Dump instruction on hyp panic
Mostafa Saleh
smostafa at google.com
Thu Jul 17 16:47:43 PDT 2025
Similar to the kernel panic, where the instruction code is printed,
we can do the same for hypervisor panics.
This patch does that only in case of “CONFIG_NVHE_EL2_DEBUG” or nvhe.
The next patch adds support for pKVM.
Also, remove the hardcoded argument dump_kernel_instr().
Signed-off-by: Mostafa Saleh <smostafa at google.com>
---
arch/arm64/include/asm/traps.h | 1 +
arch/arm64/kernel/traps.c | 20 +++++++++++++-------
arch/arm64/kvm/handle_exit.c | 5 +++++
3 files changed, 19 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h
index 82cf1f879c61..0d7e86a95d62 100644
--- a/arch/arm64/include/asm/traps.h
+++ b/arch/arm64/include/asm/traps.h
@@ -30,6 +30,7 @@ void arm64_force_sig_mceerr(int code, unsigned long far, short lsb, const char *
void arm64_force_sig_ptrace_errno_trap(int errno, unsigned long far, const char *str);
int early_brk64(unsigned long addr, unsigned long esr, struct pt_regs *regs);
+void dump_instr(unsigned long addr);
/*
* Move regs->pc to next instruction and do necessary setup before it
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 9bfa5c944379..d692c05e3686 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -149,15 +149,11 @@ pstate_check_t * const aarch32_opcode_cond_checks[16] = {
int show_unhandled_signals = 0;
-static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
+void dump_instr(unsigned long addr)
{
- unsigned long addr = instruction_pointer(regs);
char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
int i;
- if (user_mode(regs))
- return;
-
for (i = -4; i < 1; i++) {
unsigned int val, bad;
@@ -169,7 +165,17 @@ static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
p += sprintf(p, i == 0 ? "(????????) " : "???????? ");
}
- printk("%sCode: %s\n", lvl, str);
+ printk(KERN_EMERG "Code: %s\n", str);
+}
+
+static void dump_kernel_instr(struct pt_regs *regs)
+{
+ unsigned long addr = instruction_pointer(regs);
+
+ if (user_mode(regs))
+ return;
+
+ dump_instr(addr);
}
#define S_SMP " SMP"
@@ -190,7 +196,7 @@ static int __die(const char *str, long err, struct pt_regs *regs)
print_modules();
show_regs(regs);
- dump_kernel_instr(KERN_EMERG, regs);
+ dump_kernel_instr(regs);
return ret;
}
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 453266c96481..de12b4d4bccd 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -565,6 +565,11 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
/* Dump the nVHE hypervisor backtrace */
kvm_nvhe_dump_backtrace(hyp_offset);
+ /* Dump the faulting instruction */
+ if (!is_protected_kvm_enabled() ||
+ IS_ENABLED(CONFIG_NVHE_EL2_DEBUG))
+ dump_instr(panic_addr + kaslr_offset());
+
/*
* Hyp has panicked and we're going to handle that by panicking the
* kernel. The kernel offset will be revealed in the panic so we're
--
2.50.0.727.gbf7dc18ff4-goog
More information about the linux-arm-kernel
mailing list