@@ -176,6 +176,22 @@ struct kvm_nvhe_init_params {
unsigned long vtcr;
};
+/**
+ * Used by the host in EL1 to dump the nVHE hypervisor backtrace on
+ * hyp_panic() in non-protected mode.
+ *
+ * @stack_base: hyp VA of the hyp_stack base.
+ * @overflow_stack_base: hyp VA of the hyp_overflow_stack base.
+ * @fp: hyp FP where the backtrace begins.
+ * @pc: hyp PC where the backtrace begins.
+ */
+struct kvm_nvhe_stacktrace_info {
+ unsigned long stack_base;
+ unsigned long overflow_stack_base;
+ unsigned long fp;
+ unsigned long pc;
+};
+
/* Translate a kernel address @ptr into its equivalent linear mapping */
#define kvm_ksym_ref(ptr) \
({ \
@@ -19,6 +19,7 @@
#ifndef __ASM_STACKTRACE_NVHE_H
#define __ASM_STACKTRACE_NVHE_H
+#include <asm/kvm_asm.h>
#include <asm/stacktrace/common.h>
/**
@@ -49,6 +50,9 @@ static inline bool on_accessible_stack(const struct task_struct *tsk,
*/
#ifdef __KVM_NVHE_HYPERVISOR__
+DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
+DECLARE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
+
extern void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc);
#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE
@@ -9,6 +9,28 @@
DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack)
__aligned(16);
+DEFINE_PER_CPU(struct kvm_nvhe_stacktrace_info, kvm_stacktrace_info);
+
+/**
+ * hyp_prepare_backtrace - Prepare non-protected nVHE backtrace.
+ *
+ * @fp : frame pointer at which to start the unwinding.
+ * @pc : program counter at which to start the unwinding.
+ *
+ * Save the information needed by the host to unwind the non-protected
+ * nVHE hypervisor stack in EL1.
+ */
+static void hyp_prepare_backtrace(unsigned long fp, unsigned long pc)
+{
+ struct kvm_nvhe_stacktrace_info *stacktrace_info = this_cpu_ptr(&kvm_stacktrace_info);
+ struct kvm_nvhe_init_params *params = this_cpu_ptr(&kvm_init_params);
+
+ stacktrace_info->stack_base = (unsigned long)(params->stack_hyp_va - PAGE_SIZE);
+ stacktrace_info->overflow_stack_base = (unsigned long)this_cpu_ptr(overflow_stack);
+ stacktrace_info->fp = fp;
+ stacktrace_info->pc = pc;
+}
+
#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE
DEFINE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)], pkvm_stacktrace);
@@ -81,4 +103,6 @@ void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc)
{
if (is_protected_kvm_enabled())
pkvm_save_backtrace(fp, pc);
+ else
+ hyp_prepare_backtrace(fp, pc);
}
In non-protected nVHE mode (non-pKVM) the host can directly access hypervisor memory; and unwinding of the hypervisor stacktrace is done from EL1 to save on memory for shared buffers. To unwind the hypervisor stack from EL1 the host needs to know the starting point for the unwind and information that will allow it to translate hypervisor stack addresses to the corresponding kernel addresses. This patch sets up this book keeping. It is made use of later in the series. Signed-off-by: Kalesh Singh <kaleshsingh@google.com> --- arch/arm64/include/asm/kvm_asm.h | 16 ++++++++++++++++ arch/arm64/include/asm/stacktrace/nvhe.h | 4 ++++ arch/arm64/kvm/hyp/nvhe/stacktrace.c | 24 ++++++++++++++++++++++++ 3 files changed, 44 insertions(+)