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KVM: arm64: Move nVHE stacktrace unwinding into its own compilation unit

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The unwinding code doesn't really belong to the exit handling
code. Instead, move it to a file (conveniently named stacktrace.c
to confuse the reviewer), and move all the stacktrace-related
stuff there.

It will be joined by more code very soon.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Tested-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20220727142906.1856759-3-maz@kernel.org
This commit is contained in:
Marc Zyngier 2022-07-27 15:29:02 +01:00
parent 03fe9cd05b
commit 9f5fee05f6
4 changed files with 123 additions and 99 deletions
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2
arch/arm64/include/asm/stacktrace/nvhe.h
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@ -172,5 +172,7 @@ static inline int notrace unwind_next(struct unwind_state *state)
}
NOKPROBE_SYMBOL(unwind_next);
void kvm_nvhe_dump_backtrace(unsigned long hyp_offset);
#endif /* __KVM_NVHE_HYPERVISOR__ */
#endif /* __ASM_STACKTRACE_NVHE_H */

2
arch/arm64/kvm/Makefile
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@ -12,7 +12,7 @@ obj-$(CONFIG_KVM) += hyp/
kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
inject_fault.o va_layout.o handle_exit.o \
guest.o debug.o reset.o sys_regs.o \
guest.o debug.o reset.o sys_regs.o stacktrace.o \
vgic-sys-reg-v3.o fpsimd.o pkvm.o \
arch_timer.o trng.o vmid.o \
vgic/vgic.o vgic/vgic-init.o \

98
arch/arm64/kvm/handle_exit.c
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@ -319,104 +319,6 @@ void handle_exit_early(struct kvm_vcpu *vcpu, int exception_index)
kvm_handle_guest_serror(vcpu, kvm_vcpu_get_esr(vcpu));
}
/*
* kvm_nvhe_dump_backtrace_entry - Symbolize and print an nVHE backtrace entry
*
* @arg : the hypervisor offset, used for address translation
* @where : the program counter corresponding to the stack frame
*/
static bool kvm_nvhe_dump_backtrace_entry(void *arg, unsigned long where)
{
unsigned long va_mask = GENMASK_ULL(vabits_actual - 1, 0);
unsigned long hyp_offset = (unsigned long)arg;
/* Mask tags and convert to kern addr */
where = (where & va_mask) + hyp_offset;
kvm_err(" [<%016lx>] %pB\n", where, (void *)(where + kaslr_offset()));
return true;
}
static inline void kvm_nvhe_dump_backtrace_start(void)
{
kvm_err("nVHE call trace:\n");
}
static inline void kvm_nvhe_dump_backtrace_end(void)
{
kvm_err("---[ end nVHE call trace ]---\n");
}
/*
* hyp_dump_backtrace - Dump the non-protected nVHE backtrace.
*
* @hyp_offset: hypervisor offset, used for address translation.
*
* The host can directly access HYP stack pages in non-protected
* mode, so the unwinding is done directly from EL1. This removes
* the need for shared buffers between host and hypervisor for
* the stacktrace.
*/
static void hyp_dump_backtrace(unsigned long hyp_offset)
{
struct kvm_nvhe_stacktrace_info *stacktrace_info;
struct unwind_state state;
stacktrace_info = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
kvm_nvhe_unwind_init(&state, stacktrace_info->fp, stacktrace_info->pc);
kvm_nvhe_dump_backtrace_start();
unwind(&state, kvm_nvhe_dump_backtrace_entry, (void *)hyp_offset);
kvm_nvhe_dump_backtrace_end();
}
#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE
DECLARE_KVM_NVHE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)],
pkvm_stacktrace);
/*
* pkvm_dump_backtrace - Dump the protected nVHE HYP backtrace.
*
* @hyp_offset: hypervisor offset, used for address translation.
*
* Dumping of the pKVM HYP backtrace is done by reading the
* stack addresses from the shared stacktrace buffer, since the
* host cannot directly access hypervisor memory in protected
* mode.
*/
static void pkvm_dump_backtrace(unsigned long hyp_offset)
{
unsigned long *stacktrace
= (unsigned long *) this_cpu_ptr_nvhe_sym(pkvm_stacktrace);
int i, size = NVHE_STACKTRACE_SIZE / sizeof(long);
kvm_nvhe_dump_backtrace_start();
/* The saved stacktrace is terminated by a null entry */
for (i = 0; i < size && stacktrace[i]; i++)
kvm_nvhe_dump_backtrace_entry((void *)hyp_offset, stacktrace[i]);
kvm_nvhe_dump_backtrace_end();
}
#else /* !CONFIG_PROTECTED_NVHE_STACKTRACE */
static void pkvm_dump_backtrace(unsigned long hyp_offset)
{
kvm_err("Cannot dump pKVM nVHE stacktrace: !CONFIG_PROTECTED_NVHE_STACKTRACE\n");
}
#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */
/*
* kvm_nvhe_dump_backtrace - Dump KVM nVHE hypervisor backtrace.
*
* @hyp_offset: hypervisor offset, used for address translation.
*/
static void kvm_nvhe_dump_backtrace(unsigned long hyp_offset)
{
if (is_protected_kvm_enabled())
pkvm_dump_backtrace(hyp_offset);
else
hyp_dump_backtrace(hyp_offset);
}
void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
u64 elr_virt, u64 elr_phys,
u64 par, uintptr_t vcpu,

120
arch/arm64/kvm/stacktrace.c Normal file
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@ -0,0 +1,120 @@
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* KVM nVHE hypervisor stack tracing support.
*
* The unwinder implementation depends on the nVHE mode:
*
* 1) Non-protected nVHE mode - the host can directly access the
* HYP stack pages and unwind the HYP stack in EL1. This saves having
* to allocate shared buffers for the host to read the unwinded
* stacktrace.
*
* 2) pKVM (protected nVHE) mode - the host cannot directly access
* the HYP memory. The stack is unwinded in EL2 and dumped to a shared
* buffer where the host can read and print the stacktrace.
*
* Copyright (C) 2022 Google LLC
*/
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <asm/stacktrace/nvhe.h>
/*
* kvm_nvhe_dump_backtrace_entry - Symbolize and print an nVHE backtrace entry
*
* @arg : the hypervisor offset, used for address translation
* @where : the program counter corresponding to the stack frame
*/
static bool kvm_nvhe_dump_backtrace_entry(void *arg, unsigned long where)
{
unsigned long va_mask = GENMASK_ULL(vabits_actual - 1, 0);
unsigned long hyp_offset = (unsigned long)arg;
/* Mask tags and convert to kern addr */
where = (where & va_mask) + hyp_offset;
kvm_err(" [<%016lx>] %pB\n", where, (void *)(where + kaslr_offset()));
return true;
}
static void kvm_nvhe_dump_backtrace_start(void)
{
kvm_err("nVHE call trace:\n");
}
static void kvm_nvhe_dump_backtrace_end(void)
{
kvm_err("---[ end nVHE call trace ]---\n");
}
/*
* hyp_dump_backtrace - Dump the non-protected nVHE backtrace.
*
* @hyp_offset: hypervisor offset, used for address translation.
*
* The host can directly access HYP stack pages in non-protected
* mode, so the unwinding is done directly from EL1. This removes
* the need for shared buffers between host and hypervisor for
* the stacktrace.
*/
static void hyp_dump_backtrace(unsigned long hyp_offset)
{
struct kvm_nvhe_stacktrace_info *stacktrace_info;
struct unwind_state state;
stacktrace_info = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
kvm_nvhe_unwind_init(&state, stacktrace_info->fp, stacktrace_info->pc);
kvm_nvhe_dump_backtrace_start();
unwind(&state, kvm_nvhe_dump_backtrace_entry, (void *)hyp_offset);
kvm_nvhe_dump_backtrace_end();
}
#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE
DECLARE_KVM_NVHE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)],
pkvm_stacktrace);
/*
* pkvm_dump_backtrace - Dump the protected nVHE HYP backtrace.
*
* @hyp_offset: hypervisor offset, used for address translation.
*
* Dumping of the pKVM HYP backtrace is done by reading the
* stack addresses from the shared stacktrace buffer, since the
* host cannot directly access hypervisor memory in protected
* mode.
*/
static void pkvm_dump_backtrace(unsigned long hyp_offset)
{
unsigned long *stacktrace
= (unsigned long *) this_cpu_ptr_nvhe_sym(pkvm_stacktrace);
int i, size = NVHE_STACKTRACE_SIZE / sizeof(long);
kvm_nvhe_dump_backtrace_start();
/* The saved stacktrace is terminated by a null entry */
for (i = 0; i < size && stacktrace[i]; i++)
kvm_nvhe_dump_backtrace_entry((void *)hyp_offset, stacktrace[i]);
kvm_nvhe_dump_backtrace_end();
}
#else /* !CONFIG_PROTECTED_NVHE_STACKTRACE */
static void pkvm_dump_backtrace(unsigned long hyp_offset)
{
kvm_err("Cannot dump pKVM nVHE stacktrace: !CONFIG_PROTECTED_NVHE_STACKTRACE\n");
}
#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */
/*
* kvm_nvhe_dump_backtrace - Dump KVM nVHE hypervisor backtrace.
*
* @hyp_offset: hypervisor offset, used for address translation.
*/
void kvm_nvhe_dump_backtrace(unsigned long hyp_offset)
{
if (is_protected_kvm_enabled())
pkvm_dump_backtrace(hyp_offset);
else
hyp_dump_backtrace(hyp_offset);
}