From: Charlie Jenkins <[email protected]> Create a KVM test device to help verify mmio reads and write emulation. This is a simple device that will store the data in a buffer on writes and echo back that stored data on a read.
Signed-off-by: Charlie Jenkins <[email protected]> --- include/uapi/linux/kvm.h | 2 + lib/Kconfig.debug | 6 +++ virt/kvm/Kconfig.debug | 16 ++++++++ virt/kvm/Makefile.kvm | 1 + virt/kvm/kvm_main.c | 8 ++++ virt/kvm/mmio_test.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++ virt/kvm/mmio_test.h | 18 +++++++++ 7 files changed, 146 insertions(+) diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index dddb781b0507..9e2918614246 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1209,6 +1209,8 @@ enum kvm_device_type { #define KVM_DEV_TYPE_LOONGARCH_EIOINTC KVM_DEV_TYPE_LOONGARCH_EIOINTC KVM_DEV_TYPE_LOONGARCH_PCHPIC, #define KVM_DEV_TYPE_LOONGARCH_PCHPIC KVM_DEV_TYPE_LOONGARCH_PCHPIC + KVM_DEV_TYPE_TEST, +#define KVM_DEV_TYPE_TEST KVM_DEV_TYPE_TEST KVM_DEV_TYPE_MAX, diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index ba36939fda79..7a4a23d1fc9e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -717,6 +717,12 @@ source "net/Kconfig.debug" endmenu # "Networking Debugging" +menu "KVM Debugging" + +source "virt/kvm/Kconfig.debug" + +endmenu # "KVM Debugging" + menu "Memory Debugging" source "mm/Kconfig.debug" diff --git a/virt/kvm/Kconfig.debug b/virt/kvm/Kconfig.debug new file mode 100644 index 000000000000..d24709f5bcbf --- /dev/null +++ b/virt/kvm/Kconfig.debug @@ -0,0 +1,16 @@ +# SPDX-License-Identifier: GPL-2.0-only + +config KVM_MMIO_TEST + bool "Enable kvm mmio testing" + depends on KVM + depends on KVM_MMIO + default n + help + Enable testing for kvm mmio. This is a test-only mmio device that + stores writes in a buffer and returns the buffered data on a read. + + This is useful for testing the kvm mmio emulation code. Enabling + this does not run any tests, just builds in the support for the test + device into the kernel. + + If unsure, say N. diff --git a/virt/kvm/Makefile.kvm b/virt/kvm/Makefile.kvm index d047d4cf58c9..bd4da8c23923 100644 --- a/virt/kvm/Makefile.kvm +++ b/virt/kvm/Makefile.kvm @@ -8,6 +8,7 @@ KVM ?= ../../../virt/kvm kvm-y := $(KVM)/kvm_main.o $(KVM)/eventfd.o $(KVM)/binary_stats.o kvm-$(CONFIG_KVM_VFIO) += $(KVM)/vfio.o kvm-$(CONFIG_KVM_MMIO) += $(KVM)/coalesced_mmio.o +kvm-$(CONFIG_KVM_MMIO_TEST) += $(KVM)/mmio_test.o kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o kvm-$(CONFIG_HAVE_KVM_IRQ_ROUTING) += $(KVM)/irqchip.o kvm-$(CONFIG_HAVE_KVM_DIRTY_RING) += $(KVM)/dirty_ring.o diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5fcd401a5897..a0b143e71560 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -59,6 +59,7 @@ #include "async_pf.h" #include "kvm_mm.h" #include "vfio.h" +#include "mmio_test.h" #include <trace/events/ipi.h> @@ -6528,6 +6529,10 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module) if (WARN_ON_ONCE(r)) goto err_vfio; + r = kvm_mmio_test_ops_init(); + if (WARN_ON_ONCE(r)) + goto err_mmio_test; + r = kvm_gmem_init(module); if (r) goto err_gmem; @@ -6555,6 +6560,8 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module) err_gmem: kvm_vfio_ops_exit(); err_vfio: + kvm_mmio_test_ops_exit(); +err_mmio_test: kvm_async_pf_deinit(); err_async_pf: kvm_irqfd_exit(); @@ -6585,6 +6592,7 @@ void kvm_exit(void) free_cpumask_var(per_cpu(cpu_kick_mask, cpu)); kmem_cache_destroy(kvm_vcpu_cache); kvm_gmem_exit(); + kvm_mmio_test_ops_exit(); kvm_vfio_ops_exit(); kvm_async_pf_deinit(); kvm_irqfd_exit(); diff --git a/virt/kvm/mmio_test.c b/virt/kvm/mmio_test.c new file mode 100644 index 000000000000..fa84c2b4c5fc --- /dev/null +++ b/virt/kvm/mmio_test.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * mmio_test.c - Kernel module side for testing the KVM riscv mmio functionality. + */ + +#include <linux/kvm_host.h> + +#include <kvm/iodev.h> +#include "mmio_test.h" + +struct mmio_test { + struct kvm *kvm; + struct kvm_io_device dev; + unsigned long start; + unsigned long size; + char cache[16]; +}; + +static struct mmio_test *kvm_to_mmio_test_dev(const struct kvm_io_device *dev) +{ + return container_of(dev, struct mmio_test, dev); +} + +static int mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, + gpa_t addr, int len, void *val) +{ + struct mmio_test *mmio_test = kvm_to_mmio_test_dev(dev); + + if ((addr - mmio_test->start) >= mmio_test->size) + return -1; + + /* Write back cached value */ + memcpy(val, &mmio_test->cache[(addr - mmio_test->start)], len); + return 0; +} + +static int mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, + gpa_t addr, int len, const void *val) +{ + struct mmio_test *mmio_test = kvm_to_mmio_test_dev(dev); + + if ((addr - mmio_test->start) >= mmio_test->size) + return -1; + + /* Cache value */ + memcpy(&mmio_test->cache[(addr - mmio_test->start)], val, len); + return 0; +} + +static const struct kvm_io_device_ops mmio_ops = { + .read = mmio_read, + .write = mmio_write, +}; + +static int mmio_test_create(struct kvm_device *dev, u32 type) +{ + struct mmio_test *mmio_test; + + mmio_test = kzalloc(sizeof(*mmio_test), GFP_KERNEL); + if (!mmio_test) + return -ENOMEM; + + mmio_test->start = 0x20000000; + mmio_test->size = 0x16; + + dev->private = mmio_test; + + kvm_iodevice_init(&mmio_test->dev, &mmio_ops); + kvm_io_bus_register_dev(dev->kvm, KVM_MMIO_BUS, mmio_test->start, + mmio_test->size, &mmio_test->dev); + + return 0; +} + +static void mmio_test_release(struct kvm_device *dev) +{ + kfree(dev->private); +} + +struct kvm_device_ops kvm_riscv_mmio_test_device_ops = { + .name = "kvm-riscv-mmio_test", + .create = mmio_test_create, + .release = mmio_test_release, +}; + +int kvm_mmio_test_ops_init(void) +{ + return kvm_register_device_ops(&kvm_riscv_mmio_test_device_ops, + KVM_DEV_TYPE_TEST); +} + +void kvm_mmio_test_ops_exit(void) +{ + kvm_unregister_device_ops(KVM_DEV_TYPE_TEST); +} diff --git a/virt/kvm/mmio_test.h b/virt/kvm/mmio_test.h new file mode 100644 index 000000000000..49a6e900eec9 --- /dev/null +++ b/virt/kvm/mmio_test.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __KVM_MMIO_TEST_H +#define __KVM_MMIO_TEST_H + +#ifdef CONFIG_KVM_MMIO_TEST +int kvm_mmio_test_ops_init(void); +void kvm_mmio_test_ops_exit(void); +#else +static inline int kvm_mmio_test_ops_init(void) +{ + return 0; +} +static inline void kvm_mmio_test_ops_exit(void) +{ +} +#endif + +#endif -- 2.52.0
