@@ -179,13 +179,18 @@ SYM_FUNC_END(__host_hvc)
b hyp_panic
.L__hyp_sp_overflow\@:
+#ifdef CONFIG_NVHE_EL2_DEBUG
+ /* Switch to the overflow stack */
+ adr_this_cpu sp, hyp_overflow_stack + PAGE_SIZE, x0
+#else
/*
- * 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.
+ * If !CONFIG_NVHE_EL2_DEBUG, 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
+#endif
bl hyp_panic_bad_stack
ASM_BUG()
@@ -34,6 +34,11 @@ DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);
DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
DEFINE_PER_CPU(unsigned long, kvm_hyp_vector);
+#ifdef CONFIG_NVHE_EL2_DEBUG
+DEFINE_PER_CPU(unsigned long [PAGE_SIZE/sizeof(long)], hyp_overflow_stack)
+ __aligned(16);
+#endif
+
static void __activate_traps(struct kvm_vcpu *vcpu)
{
u64 val;
Allocate and switch to 16-byte aligned secondary stack on overflow. This provides us stack space to better handle overflows; and is used in a subsequent patch to dump the hypervisor stacktrace. The overflow stack is only allocated if CONFIG_NVHE_EL2_DEBUG is enabled, as hypervisor stacktraces is a debug feature dependent on CONFIG_NVHE_EL2_DEBUG. Signed-off-by: Kalesh Singh <kaleshsingh@google.com> --- Changes in v4: - Update comment to clarify resetting the SP to the top of the stack only happens if CONFIG_NVHE_EL2_DEBUG is disabled, per Fuad arch/arm64/kvm/hyp/nvhe/host.S | 11 ++++++++--- arch/arm64/kvm/hyp/nvhe/switch.c | 5 +++++ 2 files changed, 13 insertions(+), 3 deletions(-)