[kvm-devel] [RFC][PATCH 2/4] kvm: Arch-specifc KVM_EXIT_DEBUG payload

[Jan K. <jan...@we...>]

This adds an arch field to kvm_run.debug, the payload that is returned
to user space on KVM_EXIT_DEBUG guest exits. For x86, this field is now
supposed to report the precise debug exception (#DB or #BP) and the
current state of the debug registers (the latter is not yet
implemented).

---
 arch/x86/kvm/vmx.c    |    1 +
 include/asm-x86/kvm.h |    5 +++++
 include/linux/kvm.h   |    1 +
 3 files changed, 7 insertions(+)

Index: b/arch/x86/kvm/vmx.c
===================================================================
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2282,6 +2282,7 @@ static int handle_exception(struct kvm_v
 	if ((intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK)) ==
 	    (INTR_TYPE_EXCEPTION | 1)) {
 		kvm_run->exit_reason = KVM_EXIT_DEBUG;
+		kvm_run->debug.arch.exception = 1;
 		return 0;
 	}
 	kvm_run->exit_reason = KVM_EXIT_EXCEPTION;
Index: b/include/asm-x86/kvm.h
===================================================================
--- a/include/asm-x86/kvm.h
+++ b/include/asm-x86/kvm.h
@@ -230,4 +230,9 @@ struct kvm_pit_state {
 #define KVM_TRC_APIC_ACCESS      (KVM_TRC_HANDLER + 0x14)
 #define KVM_TRC_TDP_FAULT        (KVM_TRC_HANDLER + 0x15)
 
+struct kvm_debug_exit_arch {
+	__u32 exception;
+	__u64 dr[8];
+};
+
 #endif
Index: b/include/linux/kvm.h
===================================================================
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -125,6 +125,7 @@ struct kvm_run {
 			__u64 data_offset; /* relative to kvm_run start */
 		} io;
 		struct {
+			struct kvm_debug_exit_arch arch;
 		} debug;
 		/* KVM_EXIT_MMIO */
 		struct {