executor: arm64: add SYZOS_API_MRS

Add support for the MRS instruction in a similar manner to MSR.

4 files changed, 47 insertions, 0 deletions

diff --git a/sys/linux/dev_kvm_arm64.txt b/sys/linux/dev_kvm_arm64.txt
index 686cf2575..aff892a5f 100644
--- a/sys/linux/dev_kvm_arm64.txt
+++ b/sys/linux/dev_kvm_arm64.txt
@@ -100,6 +100,10 @@ syzos_api_code {
 	ret	const[0xd65f03c0, int32]
 } [packed]
 
+syzos_api_mrs {
+	arg_reg	flags[kvm_regs_arm64_sys, int64]
+}
+
 syzos_api_msr {
 	arg_reg		flags[kvm_regs_arm64_sys, int64]
 	arg_value	int64
@@ -207,4 +211,5 @@ syzos_api_call [
 	memwrite	syzos_api[6, syzos_api_memwrite]
 	its_setup	syzos_api[7, syzos_api_its_setup]
 	its_send_cmd	syzos_api[8, syzos_api_its_send_cmd]
+	mrs		syzos_api[9, syzos_api_mrs]
 ] [varlen]
diff --git a/sys/linux/test/arm64-syz_kvm_setup_syzos_vm-enable-pmu-mrs b/sys/linux/test/arm64-syz_kvm_setup_syzos_vm-enable-pmu-mrs
new file mode 100644
index 000000000..d0bf5b073
--- /dev/null
+++ b/sys/linux/test/arm64-syz_kvm_setup_syzos_vm-enable-pmu-mrs
@@ -0,0 +1,25 @@
+#
+# requires: arch=arm64 -threaded
+#
+r0 = openat$kvm(0, &AUTO='/dev/kvm\x00', 0x0, 0x0)
+r1 = ioctl$KVM_CREATE_VM(r0, AUTO, 0x0)
+r2 = syz_kvm_setup_syzos_vm(r1, &(0x7f0000c00000/0x400000)=nil)
+#
+# 0x603000000013df40 is PMEVCNTR0_EL0, write to it will trigger access_pmu_evcntr() in arch/arm64/kvm/sys_regs.c
+# This is done to illustrate that PMU is accessible.
+# 0x8 corresponds to the KVM_ARM_VCPU_PMU_V3 feature bit and is required to enable PMU.
+#
+r3 = syz_kvm_add_vcpu(r2, &AUTO={0x0, &AUTO=[@mrs={AUTO, AUTO, {0x603000000013df40}}], AUTO}, &AUTO=[@featur1={0x1, 0x8}], 0x1)
+#
+# Call ioctl(KVM_SET_DEVICE_ATTR) with group=KVM_ARM_VCPU_PMU_V3_CTRL and attr=KVM_ARM_VCPU_PMU_V3_INIT,
+# as per https://www.kernel.org/doc/Documentation/virt/kvm/devices/vcpu.rst.
+#
+ioctl$KVM_SET_DEVICE_ATTR_vcpu(r3, AUTO, &AUTO=@attr_pmu_init)
+
+r4 = ioctl$KVM_GET_VCPU_MMAP_SIZE(r0, AUTO)
+r5 = mmap$KVM_VCPU(&(0x7f0000009000/0x1000)=nil, r4, 0x3, 0x1, r3, 0x0)
+#
+# Run till the end of guest_main(). 0xffffffffffffffff is UEXIT_END.
+#
+ioctl$KVM_RUN(r3, AUTO, 0x0)
+syz_kvm_assert_syzos_uexit(r5, 0xffffffffffffffff)
diff --git a/sys/linux/test/arm64-syz_kvm_setup_syzos_vm-enable-pmu b/sys/linux/test/arm64-syz_kvm_setup_syzos_vm-enable-pmu-msr
index eee1ce9db..eee1ce9db 100644
--- a/sys/linux/test/arm64-syz_kvm_setup_syzos_vm-enable-pmu
+++ b/sys/linux/test/arm64-syz_kvm_setup_syzos_vm-enable-pmu-msr
diff --git a/sys/linux/test/arm64-syz_kvm_setup_syzos_vm-mrs b/sys/linux/test/arm64-syz_kvm_setup_syzos_vm-mrs
new file mode 100644
index 000000000..d5a6c5bb6
--- /dev/null
+++ b/sys/linux/test/arm64-syz_kvm_setup_syzos_vm-mrs
@@ -0,0 +1,17 @@
+#
+# requires: arch=arm64 -threaded
+#
+r0 = openat$kvm(0, &AUTO='/dev/kvm\x00', 0x0, 0x0)
+r1 = ioctl$KVM_CREATE_VM(r0, AUTO, 0x0)
+r2 = syz_kvm_setup_syzos_vm(r1, &(0x7f0000c00000/0x400000)=nil)
+#
+# 0x6030000000138010 is MDCCINT_EL1.
+#
+r3 = syz_kvm_add_vcpu(r2, &AUTO={0x0, &AUTO=[@mrs={AUTO, AUTO, {0x6030000000138010}}], AUTO}, 0x0, 0x0)
+r4 = ioctl$KVM_GET_VCPU_MMAP_SIZE(r0, AUTO)
+r5 = mmap$KVM_VCPU(&(0x7f0000009000/0x1000)=nil, r4, 0x3, 0x1, r3, 0x0)
+
+# Run till the end of guest_main(). 0xffffffffffffffff is UEXIT_END.
+#
+ioctl$KVM_RUN(r3, AUTO, 0x0)
+syz_kvm_assert_syzos_uexit(r5, 0xffffffffffffffff)