This vm ioctl adds or removes an ioregionfd MMIO/PIO region. Guest
read and write accesses are dispatched through the given ioregionfd
instead of returning from ioctl(KVM_RUN). Regions can be deleted by
setting fds to -1.
Signed-off-by: Elena Afanasova <eafanasova@xxxxxxxxx>
---
Changes in v2:
- changes after code review
arch/x86/kvm/Kconfig | 1 +
arch/x86/kvm/Makefile | 1 +
arch/x86/kvm/x86.c | 1 +
include/linux/kvm_host.h | 17 +++
include/uapi/linux/kvm.h | 23 ++++
virt/kvm/Kconfig | 3 +
virt/kvm/eventfd.c | 25 +++++
virt/kvm/eventfd.h | 14 +++
virt/kvm/ioregion.c | 232
+++++++++++++++++++++++++++++++++++++++
virt/kvm/ioregion.h | 15 +++
virt/kvm/kvm_main.c | 11 ++
11 files changed, 343 insertions(+)
create mode 100644 virt/kvm/eventfd.h
create mode 100644 virt/kvm/ioregion.c
create mode 100644 virt/kvm/ioregion.h
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index f92dfd8ef10d..b914ef375199 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -33,6 +33,7 @@ config KVM
select HAVE_KVM_IRQ_BYPASS
select HAVE_KVM_IRQ_ROUTING
select HAVE_KVM_EVENTFD
+ select KVM_IOREGION
select KVM_ASYNC_PF
select USER_RETURN_NOTIFIER
select KVM_MMIO
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index b804444e16d4..b3b17dc9f7d4 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -12,6 +12,7 @@ KVM := ../../../virt/kvm
kvm-y += $(KVM)/kvm_main.o
$(KVM)/coalesced_mmio.o \
$(KVM)/eventfd.o $(KVM)/irqchip.o
$(KVM)/vfio.o
kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o
+kvm-$(CONFIG_KVM_IOREGION) += $(KVM)/ioregion.o
kvm-y += x86.o emulate.o i8259.o irq.o
lapic.o \
i8254.o ioapic.o irq_comm.o cpuid.o pmu.o
mtrr.o \
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e545a8a613b1..ddb28f5ca252 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3739,6 +3739,7 @@ int kvm_vm_ioctl_check_extension(struct kvm
*kvm, long ext)
case KVM_CAP_X86_USER_SPACE_MSR:
case KVM_CAP_X86_MSR_FILTER:
case KVM_CAP_ENFORCE_PV_FEATURE_CPUID:
+ case KVM_CAP_IOREGIONFD:
r = 1;
break;
case KVM_CAP_SYNC_REGS:
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7f2e2a09ebbd..7cd667dddba9 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -470,6 +470,10 @@ struct kvm {
struct mutex resampler_lock;
} irqfds;
struct list_head ioeventfds;
+#endif
+#ifdef CONFIG_KVM_IOREGION
+ struct list_head ioregions_mmio;
+ struct list_head ioregions_pio;
#endif
struct kvm_vm_stat stat;
struct kvm_arch arch;
@@ -1262,6 +1266,19 @@ static inline int kvm_ioeventfd(struct kvm
*kvm, struct kvm_ioeventfd *args)
#endif /* CONFIG_HAVE_KVM_EVENTFD */
+#ifdef CONFIG_KVM_IOREGION
+void kvm_ioregionfd_init(struct kvm *kvm);
+int kvm_ioregionfd(struct kvm *kvm, struct kvm_ioregion *args);
+
+#else
+
+static inline void kvm_ioregionfd_init(struct kvm *kvm) {}
+static inline int kvm_ioregionfd(struct kvm *kvm, struct
kvm_ioregion *args)
+{
+ return -ENOSYS;
+}
+#endif
+
void kvm_arch_irq_routing_update(struct kvm *kvm);
static inline void kvm_make_request(int req, struct kvm_vcpu
*vcpu)
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index ca41220b40b8..81e775778c66 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -732,6 +732,27 @@ struct kvm_ioeventfd {
__u8 pad[36];
};
+enum {
+ kvm_ioregion_flag_nr_pio,
+ kvm_ioregion_flag_nr_posted_writes,
+ kvm_ioregion_flag_nr_max,
+};
+
+#define KVM_IOREGION_PIO (1 << kvm_ioregion_flag_nr_pio)
+#define KVM_IOREGION_POSTED_WRITES (1 <<
kvm_ioregion_flag_nr_posted_writes)
+
+#define KVM_IOREGION_VALID_FLAG_MASK ((1 <<
kvm_ioregion_flag_nr_max) - 1)
+
+struct kvm_ioregion {
+ __u64 guest_paddr; /* guest physical address */
+ __u64 memory_size; /* bytes */
+ __u64 user_data;
+ __s32 rfd;
+ __s32 wfd;
+ __u32 flags;
+ __u8 pad[28];
+};
+
#define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0)
#define KVM_X86_DISABLE_EXITS_HLT (1 << 1)
#define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2)
@@ -1053,6 +1074,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_X86_USER_SPACE_MSR 188
#define KVM_CAP_X86_MSR_FILTER 189
#define KVM_CAP_ENFORCE_PV_FEATURE_CPUID 190
+#define KVM_CAP_IOREGIONFD 191
#ifdef KVM_CAP_IRQ_ROUTING
@@ -1308,6 +1330,7 @@ struct kvm_vfio_spapr_tce {
struct
kvm_userspace_memory_region)
#define KVM_SET_TSS_ADDR _IO(KVMIO, 0x47)
#define KVM_SET_IDENTITY_MAP_ADDR _IOW(KVMIO, 0x48, __u64)
+#define KVM_SET_IOREGION _IOW(KVMIO, 0x49, struct
kvm_ioregion)
/* enable ucontrol for s390 */
struct kvm_s390_ucas_mapping {
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 1c37ccd5d402..5e6620bbf000 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -17,6 +17,9 @@ config HAVE_KVM_EVENTFD
bool
select EVENTFD
+config KVM_IOREGION
+ bool
+
config KVM_MMIO
bool
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index c2323c27a28b..aadb73903f8b 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -27,6 +27,7 @@
#include <trace/events/kvm.h>
#include <kvm/iodev.h>
+#include "ioregion.h"
#ifdef CONFIG_HAVE_KVM_IRQFD
@@ -755,6 +756,23 @@ static const struct kvm_io_device_ops
ioeventfd_ops = {
.destructor = ioeventfd_destructor,
};
+#ifdef CONFIG_KVM_IOREGION
+/* assumes kvm->slots_lock held */
+bool kvm_eventfd_collides(struct kvm *kvm, int bus_idx,
+ u64 start, u64 size)
+{
+ struct _ioeventfd *_p;
+
+ list_for_each_entry(_p, &kvm->ioeventfds, list)
+ if (_p->bus_idx == bus_idx &&
+ overlap(start, size, _p->addr,
+ !_p->length ? 8 : _p->length))
+ return true;
+
+ return false;
+}
+#endif
+
/* assumes kvm->slots_lock held */
static bool
ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
@@ -770,6 +788,13 @@ ioeventfd_check_collision(struct kvm *kvm,
struct _ioeventfd *p)
_p->datamatch == p->datamatch))))
return true;
+#ifdef CONFIG_KVM_IOREGION
+ if (p->bus_idx == KVM_MMIO_BUS || p->bus_idx == KVM_PIO_BUS)
+ if (kvm_ioregion_collides(kvm, p->bus_idx, p->addr,
+ !p->length ? 8 : p->length))
+ return true;
+#endif
+
return false;
}
diff --git a/virt/kvm/eventfd.h b/virt/kvm/eventfd.h
new file mode 100644
index 000000000000..73a621eebae3
--- /dev/null
+++ b/virt/kvm/eventfd.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __KVM_EVENTFD_H__
+#define __KVM_EVENTFD_H__
+
+#ifdef CONFIG_KVM_IOREGION
+bool kvm_eventfd_collides(struct kvm *kvm, int bus_idx, u64 start,
u64 size);
+#else
+static inline bool
+kvm_eventfd_collides(struct kvm *kvm, int bus_idx, u64 start, u64
size)
+{
+ return false;
+}
+#endif
+#endif
diff --git a/virt/kvm/ioregion.c b/virt/kvm/ioregion.c
new file mode 100644
index 000000000000..48ff92bca966
--- /dev/null
+++ b/virt/kvm/ioregion.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kvm_host.h>
+#include <linux/fs.h>
+#include <kvm/iodev.h>
+#include "eventfd.h"
+
+void
+kvm_ioregionfd_init(struct kvm *kvm)
+{
+ INIT_LIST_HEAD(&kvm->ioregions_mmio);
+ INIT_LIST_HEAD(&kvm->ioregions_pio);
+}
+
+struct ioregion {
+ struct list_head list;
+ u64 paddr; /* guest physical address */
+ u64 size; /* size in bytes */
+ struct file *rf;
+ struct file *wf;
+ u64 user_data; /* opaque token used by
userspace */
+ struct kvm_io_device dev;
+ bool posted_writes;
+};
+
+static inline struct ioregion *
+to_ioregion(struct kvm_io_device *dev)
+{
+ return container_of(dev, struct ioregion, dev);
+}
+
+/* assumes kvm->slots_lock held */
+static void
+ioregion_release(struct ioregion *p)
+{
+ fput(p->rf);
+ fput(p->wf);
+ list_del(&p->list);
+ kfree(p);
+}
+
+static int
+ioregion_read(struct kvm_vcpu *vcpu, struct kvm_io_device *this,
gpa_t addr,
+ int len, void *val)
+{
+ return -EOPNOTSUPP;
+}
+
+static int
+ioregion_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this,
gpa_t addr,
+ int len, const void *val)
+{
+ return -EOPNOTSUPP;
+}
+
+/*
+ * This function is called as KVM is completely shutting down. We
do not
+ * need to worry about locking just nuke anything we have as
quickly as possible
+ */
+static void
+ioregion_destructor(struct kvm_io_device *this)
+{
+ struct ioregion *p = to_ioregion(this);
+
+ ioregion_release(p);
+}
+
+static const struct kvm_io_device_ops ioregion_ops = {
+ .read = ioregion_read,
+ .write = ioregion_write,
+ .destructor = ioregion_destructor,
+};
+
+static inline struct list_head *
+get_ioregion_list(struct kvm *kvm, enum kvm_bus bus_idx)
+{
+ return (bus_idx == KVM_MMIO_BUS) ?
+ &kvm->ioregions_mmio : &kvm->ioregions_pio;
+}
+
+/* check for not overlapping case and reverse */
+inline bool
+overlap(u64 start1, u64 size1, u64 start2, u64 size2)
+{
+ u64 end1 = start1 + size1 - 1;
+ u64 end2 = start2 + size2 - 1;
+
+ return !(end1 < start2 || start1 >= end2);
+}
+
+/* assumes kvm->slots_lock held */
+bool
+kvm_ioregion_collides(struct kvm *kvm, int bus_idx,
+ u64 start, u64 size)
+{
+ struct ioregion *_p;
+ struct list_head *ioregions;
+
+ ioregions = get_ioregion_list(kvm, bus_idx);
+ list_for_each_entry(_p, ioregions, list)
+ if (overlap(start, size, _p->paddr, _p->size))
+ return true;
+
+ return false;
+}
+
+/* assumes kvm->slots_lock held */
+static bool
+ioregion_collision(struct kvm *kvm, struct ioregion *p, enum
kvm_bus bus_idx)
+{
+ if (kvm_ioregion_collides(kvm, bus_idx, p->paddr, p->size) ||
+ kvm_eventfd_collides(kvm, bus_idx, p->paddr, p->size))
+ return true;
+
+ return false;
+}
+
+static enum kvm_bus
+get_bus_from_flags(__u32 flags)
+{
+ if (flags & KVM_IOREGION_PIO)
+ return KVM_PIO_BUS;
+ return KVM_MMIO_BUS;
+}
+
+int
+kvm_set_ioregion(struct kvm *kvm, struct kvm_ioregion *args)
+{
+ struct ioregion *p;
+ struct file *rfile, *wfile;
+ enum kvm_bus bus_idx;
+ int ret = 0;
+
+ if (!args->memory_size)
+ return -EINVAL;
+ if ((args->guest_paddr + args->memory_size - 1) < args-
guest_paddr)
+ return -EINVAL;
+
+ rfile = fget(args->rfd);
+ if (!rfile)
+ return -EBADF;
