[RFC kvmtool 29/31] mmio: add arch hook for an unhandled MMIO access

[Suzuki K Poulose <suzuki.poulose@xxxxxxx>]

From: Joey Gouly <joey.gouly@xxxxxxx>

Add a hook that allows an architecture to run some code on an
unhandled MMIO access.

Signed-off-by: Joey Gouly <joey.gouly@xxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
 arm/kvm-cpu.c         | 4 ++++
 include/kvm/kvm-cpu.h | 2 ++
 mips/kvm-cpu.c        | 4 ++++
 mmio.c                | 3 +++
 powerpc/kvm-cpu.c     | 4 ++++
 riscv/kvm-cpu.c       | 4 ++++
 x86/kvm-cpu.c         | 4 ++++
 7 files changed, 25 insertions(+)

diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
index 98bc5fdf..90a15ae9 100644
--- a/arm/kvm-cpu.c
+++ b/arm/kvm-cpu.c
@@ -152,3 +152,7 @@ bool kvm_cpu__handle_exit(struct kvm_cpu *vcpu)
 void kvm_cpu__show_page_tables(struct kvm_cpu *vcpu)
 {
 }
+
+void kvm_cpu__arch_unhandled_mmio(struct kvm_cpu *vcpu)
+{
+}
diff --git a/include/kvm/kvm-cpu.h b/include/kvm/kvm-cpu.h
index 0f16f8d6..d0c40598 100644
--- a/include/kvm/kvm-cpu.h
+++ b/include/kvm/kvm-cpu.h
@@ -29,4 +29,6 @@ void kvm_cpu__show_page_tables(struct kvm_cpu *vcpu);
 void kvm_cpu__arch_nmi(struct kvm_cpu *cpu);
 void kvm_cpu__run_on_all_cpus(struct kvm *kvm, struct kvm_cpu_task *task);
 
+void kvm_cpu__arch_unhandled_mmio(struct kvm_cpu *cpu);
+
 #endif /* KVM__KVM_CPU_H */
diff --git a/mips/kvm-cpu.c b/mips/kvm-cpu.c
index 30a3de18..0ce88ac3 100644
--- a/mips/kvm-cpu.c
+++ b/mips/kvm-cpu.c
@@ -217,3 +217,7 @@ void kvm_cpu__show_code(struct kvm_cpu *vcpu)
 void kvm_cpu__show_page_tables(struct kvm_cpu *vcpu)
 {
 }
+
+void kvm_cpu__arch_unhandled_mmio(struct kvm_cpu *cpu)
+{
+}
diff --git a/mmio.c b/mmio.c
index 5a114e99..7e31079b 100644
--- a/mmio.c
+++ b/mmio.c
@@ -206,6 +206,9 @@ bool kvm__emulate_mmio(struct kvm_cpu *vcpu, u64 phys_addr, u8 *data,
 			fprintf(stderr,	"Warning: Ignoring MMIO %s at %016llx (length %u)\n",
 				to_direction(is_write),
 				(unsigned long long)phys_addr, len);
+
+		kvm_cpu__arch_unhandled_mmio(vcpu);
+
 		goto out;
 	}
 
diff --git a/powerpc/kvm-cpu.c b/powerpc/kvm-cpu.c
index 461e0a90..e0c20f9d 100644
--- a/powerpc/kvm-cpu.c
+++ b/powerpc/kvm-cpu.c
@@ -288,3 +288,7 @@ void kvm_cpu__show_page_tables(struct kvm_cpu *vcpu)
 {
 	/* Does nothing yet */
 }
+
+void kvm_cpu__arch_unhandled_mmio(struct kvm_cpu *cpu)
+{
+}
diff --git a/riscv/kvm-cpu.c b/riscv/kvm-cpu.c
index f98bd7ae..8417e361 100644
--- a/riscv/kvm-cpu.c
+++ b/riscv/kvm-cpu.c
@@ -461,3 +461,7 @@ void kvm_cpu__show_registers(struct kvm_cpu *vcpu)
 
 	kvm_cpu__show_csrs(vcpu);
 }
+
+void kvm_cpu__arch_unhandled_mmio(struct kvm_cpu *cpu)
+{
+}
diff --git a/x86/kvm-cpu.c b/x86/kvm-cpu.c
index b02ff65e..ac075ee4 100644
--- a/x86/kvm-cpu.c
+++ b/x86/kvm-cpu.c
@@ -444,3 +444,7 @@ void kvm_cpu__arch_nmi(struct kvm_cpu *cpu)
 
 	ioctl(cpu->vcpu_fd, KVM_NMI);
 }
+
+void kvm_cpu__arch_unhandled_mmio(struct kvm_cpu *cpu)
+{
+}
-- 
2.34.1