Commit 3a7e1b55 authored by Kalesh Singh's avatar Kalesh Singh Committed by Marc Zyngier
Browse files

KVM: arm64: Introduce pkvm_dump_backtrace() 



Dumps the pKVM hypervisor backtrace from EL1 by reading the unwinded
addresses from the shared stacktrace buffer.

The nVHE hyp backtrace is dumped on hyp_panic(), before panicking the
host.

[  111.623091] kvm [367]: nVHE call trace:
[  111.623215] kvm [367]:  [<ffff8000090a6570>] __kvm_nvhe_hyp_panic+0xac/0xf8
[  111.623448] kvm [367]:  [<ffff8000090a65cc>] __kvm_nvhe_hyp_panic_bad_stack+0x10/0x10
[  111.623642] kvm [367]:  [<ffff8000090a61e4>] __kvm_nvhe_recursive_death+0x24/0x34
. . .
[  111.640366] kvm [367]:  [<ffff8000090a61e4>] __kvm_nvhe_recursive_death+0x24/0x34
[  111.640467] kvm [367]:  [<ffff8000090a61e4>] __kvm_nvhe_recursive_death+0x24/0x34
[  111.640574] kvm [367]:  [<ffff8000090a5de4>] __kvm_nvhe___kvm_vcpu_run+0x30/0x40c
[  111.640676] kvm [367]:  [<ffff8000090a8b64>] __kvm_nvhe_handle___kvm_vcpu_run+0x30/0x48
[  111.640778] kvm [367]:  [<ffff8000090a88b8>] __kvm_nvhe_handle_trap+0xc4/0x128
[  111.640880] kvm [367]:  [<ffff8000090a7864>] __kvm_nvhe___host_exit+0x64/0x64
[  111.640996] kvm [367]: ---[ end nVHE call trace ]---

Signed-off-by: default avatarKalesh Singh <kaleshsingh@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-18-kaleshsingh@google.com
parent 75e9459e

arch/arm64/kvm/handle_exit.c

+34 −1
Original line number Diff line number Diff line
@@ -371,6 +371,39 @@ static void hyp_dump_backtrace(unsigned long 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.

 *
@@ -379,7 +412,7 @@ static void hyp_dump_backtrace(unsigned long hyp_offset) 
static void kvm_nvhe_dump_backtrace(unsigned long hyp_offset)

{

	if (is_protected_kvm_enabled())

		return;

		pkvm_dump_backtrace(hyp_offset);

	else

		hyp_dump_backtrace(hyp_offset);

}