From: Marc Zyngier <marc.zyngier@xxxxxxx>
Add an MMIO handling framework to the VGIC emulation:
Each register is described by its offset, size (or number of bits per
IRQ, if applicable) and the read/write handler functions. We provide
initialization macros to describe each GIC register later easily.
Separate dispatch functions for read and write accesses are connected
to the kvm_io_bus framework and binary-search for the responsible
register handler based on the offset address within the region.
We convert the incoming data (referenced by a pointer) to the host's
endianess and use pass-by-value to hand the data over to the actual
handler functions.
The register handler prototype and the endianess conversion are
courtesy of Christoffer Dall.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
Changelog RFC..v1:
- rework MMIO dispatching to use only one kvm_io_bus device
- document purpose of register region macros
- rename "this" parameter to "dev"
- change IGROUPR to be RAO (returning 1 => Group1 IRQs)
Changelog v1 .. v2:
* MASSIVE rework:
- store register_region pointer in kvm_io_bus linked struct
- replace write_mask_xxx functions with extract_bytes() implementation
- change handler functions' prototypes to take and return unsigned long
- use binary search to find matching register handler
- convert endianess of input data in dispatch_mmio_xxx functions
- improve readability of register initializer macros
- remove any GICv2/GICv3 specific functions from vgic-mmio.c
- rename file from vgic_mmio.c to vgic-mmio.c
include/kvm/vgic/vgic.h | 13 ++++
virt/kvm/arm/vgic/vgic-mmio.c | 171 ++++++++++++++++++++++++++++++++++++++++++
virt/kvm/arm/vgic/vgic-mmio.h | 77 +++++++++++++++++++
3 files changed, 261 insertions(+)
create mode 100644 virt/kvm/arm/vgic/vgic-mmio.c
create mode 100644 virt/kvm/arm/vgic/vgic-mmio.h
diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h
index 2615205..4ec1270 100644
--- a/include/kvm/vgic/vgic.h
+++ b/include/kvm/vgic/vgic.h
@@ -106,6 +106,16 @@ struct vgic_irq {
enum vgic_irq_config config; /* Level or edge */
};
+struct vgic_register_region;
+
+struct vgic_io_device {
+ gpa_t base_addr;
+ struct kvm_vcpu *redist_vcpu;
+ const struct vgic_register_region *regions;
+ int nr_regions;
+ struct kvm_io_device dev;
+};
+
struct vgic_dist {
bool in_kernel;
bool ready;
@@ -132,6 +142,9 @@ struct vgic_dist {
bool enabled;
struct vgic_irq *spis;
+
+ struct vgic_io_device dist_iodev;
+ struct vgic_io_device *redist_iodevs;
};
struct vgic_v2_cpu_if {
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
new file mode 100644
index 0000000..28b9cfe
--- /dev/null
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -0,0 +1,171 @@
+/*
+ * VGIC MMIO handling functions
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/bitops.h>
+#include <linux/bsearch.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <kvm/iodev.h>
+#include <kvm/vgic/vgic.h>
+
+#include "vgic.h"
+#include "vgic-mmio.h"
+
+/* extract @num bytes at @offset bytes offset in data */
+unsigned long extract_bytes(unsigned long data,
+ unsigned int offset, unsigned int num)
+{
+ return (data >> (offset * 8)) & GENMASK_ULL(num * 8 - 1, 0);
+}
+
+unsigned long vgic_mmio_read_raz(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len)
+{
+ return 0;
+}
+
+unsigned long vgic_mmio_read_rao(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len)
+{
+ return -1UL;
+}
+
+void vgic_mmio_write_wi(struct kvm_vcpu *vcpu, gpa_t addr,
+ unsigned int len, unsigned long val)
+{
+ /* Ignore */
+}
+
+static int match_region(const void *key, const void *elt)
+{
+ const unsigned int offset = (unsigned long)key;
+ const struct vgic_register_region *region = elt;
+
+ if (offset < region->reg_offset)
+ return -1;
+
+ if (offset >= region->reg_offset + region->len)
+ return 1;
+
+ return 0;
+}
+
+/* Find the proper register handler entry given a certain address offset. */
+static const struct vgic_register_region *
+vgic_find_mmio_region(const struct vgic_register_region *region, int nr_regions,
+ unsigned int offset)
+{
+ return bsearch((void *)(uintptr_t)offset, region, nr_regions,
+ sizeof(region[0]), match_region);
+}
+
+/*
+ * kvm_mmio_read_buf() returns a value in a format where it can be converted
+ * to a byte array and be directly observed as the guest wanted it to appear
+ * in memory if it had done the store itself, which is LE for the GIC, as the
+ * guest knows the GIC is always LE.
+ *
+ * We convert this value to the CPUs native format to deal with it as a data
+ * value.
+ */
+unsigned long vgic_data_mmio_bus_to_host(const void *val, unsigned int len)
+{
+ unsigned long data = kvm_mmio_read_buf(val, len);
+
+ switch (len) {
+ case 1:
+ return data;
+ case 2:
+ return le16_to_cpu(data);
+ case 4:
+ return le32_to_cpu(data);
+ default:
+ return le64_to_cpu(data);
+ }
+}
+
+/*
+ * kvm_mmio_write_buf() expects a value in a format such that if converted to
+ * a byte array it is observed as the guest would see it if it could perform
+ * the load directly. Since the GIC is LE, and the guest knows this, the
+ * guest expects a value in little endian format.
+ *
+ * We convert the data value from the CPUs native format to LE so that the
+ * value is returned in the proper format.
+ */
+void vgic_data_host_to_mmio_bus(void *buf, unsigned int len,
+ unsigned long data)
+{
+ switch (len) {
+ case 1:
+ break;
+ case 2:
+ data = cpu_to_le16(data);
+ break;
+ case 4:
+ data = cpu_to_le32(data);
+ break;
+ default:
+ data = cpu_to_le64(data);
+ }
+
+ kvm_mmio_write_buf(buf, len, data);
+}
+
+static
+struct vgic_io_device *kvm_to_vgic_iodev(const struct kvm_io_device *dev)
+{
+ return container_of(dev, struct vgic_io_device, dev);
+}
+
+static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
+ gpa_t addr, int len, void *val)
+{
+ struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
+ const struct vgic_register_region *region;
+ struct kvm_vcpu *r_vcpu;
+ unsigned long data;
+
+ region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
+ addr - iodev->base_addr);
+ if (!region)
+ return -EOPNOTSUPP;
+
+ r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
+ data = region->read(r_vcpu, addr, len);
+ vgic_data_host_to_mmio_bus(val, len, data);
+ return 0;
+}
+
+static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
+ gpa_t addr, int len, const void *val)
+{
+ struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
+ const struct vgic_register_region *region;
+ struct kvm_vcpu *r_vcpu;
+ unsigned long data = vgic_data_mmio_bus_to_host(val, len);
+
+ region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
+ addr - iodev->base_addr);
+ if (!region)
+ return -EOPNOTSUPP;
+
+ r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
+ region->write(r_vcpu, addr, len, data);
+ return 0;
+}
+
+struct kvm_io_device_ops kvm_io_gic_ops = {
+ .read = dispatch_mmio_read,
+ .write = dispatch_mmio_write,
+};
diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
new file mode 100644
index 0000000..18d3869
--- /dev/null
+++ b/virt/kvm/arm/vgic/vgic-mmio.h
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2015, 2016 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __KVM_ARM_VGIC_MMIO_H__
+#define __KVM_ARM_VGIC_MMIO_H__
+
+struct vgic_register_region {
+ unsigned int reg_offset;
+ unsigned int len;
+ unsigned int bits_per_irq;
+ unsigned long (*read)(struct kvm_vcpu *vcpu, gpa_t addr,
+ unsigned int len);
+ void (*write)(struct kvm_vcpu *vcpu, gpa_t addr, unsigned int len,
+ unsigned long val);
+};
+
+extern struct kvm_io_device_ops kvm_io_gic_ops;
+
+/*
+ * Some VGIC registers store per-IRQ information, with a different number
+ * of bits per IRQ. For those registers this macro is used.
+ * The _WITH_LENGTH version instantiates registers with a fixed length
+ * and is mutually exclusive with the _PER_IRQ version.
+ */
+#define REGISTER_DESC_WITH_BITS_PER_IRQ(off, read_ops, write_ops, bpi) \
+ { \
+ .reg_offset = off, \
+ .bits_per_irq = bpi, \
+ .len = bpi * 1024 / 8, \
+ .read = read_ops, \
+ .write = write_ops, \
+ }
+
+#define REGISTER_DESC_WITH_LENGTH(off, read_ops, write_ops, length) \
+ { \
+ .reg_offset = off, \
+ .bits_per_irq = 0, \
+ .len = length, \
+ .read = read_ops, \
+ .write = write_ops, \
+ }
+
+int kvm_vgic_register_mmio_region(struct kvm *kvm, struct kvm_vcpu *vcpu,
+ struct vgic_register_region *reg_desc,
+ struct vgic_io_device *region,
+ int nr_irqs, bool offset_private);
+
+unsigned long vgic_data_mmio_bus_to_host(const void *val, unsigned int len);
+
+void vgic_data_host_to_mmio_bus(void *buf, unsigned int len,
+ unsigned long data);
+
+unsigned long extract_bytes(unsigned long data,
+ unsigned int offset, unsigned int num);
+
+unsigned long vgic_mmio_read_raz(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len);
+
+unsigned long vgic_mmio_read_rao(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len);
+
+void vgic_mmio_write_wi(struct kvm_vcpu *vcpu, gpa_t addr,
+ unsigned int len, unsigned long val);
+
+#endif
--
2.7.3
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