[PATCH v6 09/15] KVM: arm64: implement basic ITS register handlers
Andre Przywara
andre.przywara at arm.com
Fri Jun 17 05:08:41 PDT 2016
Add emulation for some basic MMIO registers used in the ITS emulation.
This includes:
- GITS_{CTLR,TYPER,IIDR}
- ID registers
- GITS_{CBASER,CREADR,CWRITER}
(which implement the ITS command buffer handling)
- GITS_BASER<n>
Most of the handlers are pretty straight forward, only the CWRITER
handler is a bit more involved by taking the new its_cmd mutex and
then iterating over the command buffer.
The registers holding base addresses and attributes are sanitised before
storing them.
Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
include/kvm/vgic/vgic.h | 15 ++
include/linux/irqchip/arm-gic-v3.h | 11 ++
virt/kvm/arm/vgic/vgic-its.c | 343 +++++++++++++++++++++++++++++++++++--
virt/kvm/arm/vgic/vgic-mmio-v3.c | 15 +-
virt/kvm/arm/vgic/vgic-mmio.h | 10 ++
5 files changed, 380 insertions(+), 14 deletions(-)
diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h
index 979d8c3..891775e 100644
--- a/include/kvm/vgic/vgic.h
+++ b/include/kvm/vgic/vgic.h
@@ -22,6 +22,7 @@
#include <linux/spinlock.h>
#include <linux/types.h>
#include <kvm/iodev.h>
+#include <linux/list.h>
#define VGIC_V3_MAX_CPUS 255
#define VGIC_V2_MAX_CPUS 8
@@ -126,6 +127,20 @@ struct vgic_its {
bool enabled;
struct vgic_io_device iodev;
+
+ u64 baser_device_table;
+ u64 baser_coll_table;
+
+ /* Protects the command queue */
+ struct mutex cmd_lock;
+ u64 cbaser;
+ u32 creadr;
+ u32 cwriter;
+
+ /* Protects the device and collection lists */
+ struct mutex its_lock;
+ struct list_head device_list;
+ struct list_head collection_list;
};
struct vgic_dist {
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index 92d5da8..fe5a7fe 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -177,16 +177,26 @@
#define GITS_CREADR 0x0090
#define GITS_BASER 0x0100
#define GITS_IDREGS_BASE 0xffd0
+#define GITS_PIDR0 0xffe0
+#define GITS_PIDR1 0xffe4
#define GITS_PIDR2 GICR_PIDR2
+#define GITS_PIDR4 0xffd0
+#define GITS_CIDR0 0xfff0
+#define GITS_CIDR1 0xfff4
+#define GITS_CIDR2 0xfff8
+#define GITS_CIDR3 0xfffc
#define GITS_TRANSLATER 0x10040
#define GITS_CTLR_ENABLE (1U << 0)
#define GITS_CTLR_QUIESCENT (1U << 31)
+#define GITS_TYPER_PLPIS (1UL << 0)
+#define GITS_TYPER_IDBITS_SHIFT 8
#define GITS_TYPER_DEVBITS_SHIFT 13
#define GITS_TYPER_DEVBITS(r) ((((r) >> GITS_TYPER_DEVBITS_SHIFT) & 0x1f) + 1)
#define GITS_TYPER_PTA (1UL << 19)
+#define GITS_TYPER_HWCOLLCNT_SHIFT 24
#define GITS_CBASER_VALID (1UL << 63)
#define GITS_CBASER_nCnB (0UL << 59)
@@ -214,6 +224,7 @@
#define GITS_BASER_WaWb (5UL << 59)
#define GITS_BASER_RaWaWt (6UL << 59)
#define GITS_BASER_RaWaWb (7UL << 59)
+#define GITS_BASER_CACHEABILITY_SHIFT (59)
#define GITS_BASER_CACHEABILITY_MASK (7UL << 59)
#define GITS_BASER_TYPE_SHIFT (56)
#define GITS_BASER_TYPE(r) (((r) >> GITS_BASER_TYPE_SHIFT) & 7)
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 4ae3c82..d7f8834 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -21,6 +21,7 @@
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/interrupt.h>
+#include <linux/list.h>
#include <linux/uaccess.h>
#include <linux/irqchip/arm-gic-v3.h>
@@ -32,6 +33,289 @@
#include "vgic.h"
#include "vgic-mmio.h"
+struct its_device {
+ struct list_head dev_list;
+
+ /* the head for the list of ITTEs */
+ struct list_head itt_head;
+ u32 device_id;
+};
+
+#define COLLECTION_NOT_MAPPED ((u32)-1)
+
+struct its_collection {
+ struct list_head coll_list;
+
+ u32 collection_id;
+ u32 target_addr;
+};
+
+#define its_is_collection_mapped(coll) ((coll) && \
+ ((coll)->target_addr != COLLECTION_NOT_MAPPED))
+
+struct its_itte {
+ struct list_head itte_list;
+
+ struct its_collection *collection;
+ u32 lpi;
+ u32 event_id;
+};
+
+#define CBASER_ADDRESS(x) ((x) & GENMASK_ULL(51, 12))
+#define BASER_ADDRESS(x) ((x) & GENMASK_ULL(47, 12))
+
+#define ITS_FRAME(addr) ((addr) & ~(SZ_64K - 1))
+
+static unsigned long vgic_mmio_read_its_ctlr(struct kvm *vcpu,
+ struct vgic_its *its,
+ gpa_t addr, unsigned int len)
+{
+ u32 reg = 0;
+
+ mutex_lock(&its->cmd_lock);
+ if (its->creadr == its->cwriter)
+ reg |= GITS_CTLR_QUIESCENT;
+ if (its->enabled)
+ reg |= GITS_CTLR_ENABLE;
+ mutex_unlock(&its->cmd_lock);
+
+ return reg;
+}
+
+static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ its->enabled = !!(val & GITS_CTLR_ENABLE);
+}
+
+static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
+ struct vgic_its *its,
+ gpa_t addr, unsigned int len)
+{
+ u64 reg = GITS_TYPER_PLPIS;
+
+ /*
+ * We use linear CPU numbers for redistributor addressing,
+ * so GITS_TYPER.PTA is 0.
+ * Also we force all PROPBASER registers to be the same, so
+ * CommonLPIAff is 0 as well.
+ * As we hold all LPI mapping related data structures in the kernel
+ * (mimicing what the spec describes as "held in hardware"), we can
+ * claim to support a high number of "hardware" mapped collections
+ * (since we use linked lists to store them).
+ * However to avoid memory waste, we keep the number of IDBits and
+ * DevBits low - as least for the time being.
+ */
+ reg |= 0xff << GITS_TYPER_HWCOLLCNT_SHIFT;
+ reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
+ reg |= 0x0f << GITS_TYPER_IDBITS_SHIFT;
+
+ return extract_bytes(reg, addr & 7, len);
+}
+
+static unsigned long vgic_mmio_read_its_iidr(struct kvm *kvm,
+ struct vgic_its *its,
+ gpa_t addr, unsigned int len)
+{
+ return (PRODUCT_ID_KVM << 24) | (IMPLEMENTER_ARM << 0);
+}
+
+static unsigned long vgic_mmio_read_its_idregs(struct kvm *kvm,
+ struct vgic_its *its,
+ gpa_t addr, unsigned int len)
+{
+ switch (addr & 0xffff) {
+ case GITS_PIDR0:
+ return 0x92; /* part number, bits[7:0] */
+ case GITS_PIDR1:
+ return 0xb4; /* part number, bits[11:8] */
+ case GITS_PIDR2:
+ return GIC_PIDR2_ARCH_GICv3 | 0x0b;
+ case GITS_PIDR4:
+ return 0x40; /* This is a 64K software visible page */
+ /* The following are the ID registers for (any) GIC. */
+ case GITS_CIDR0:
+ return 0x0d;
+ case GITS_CIDR1:
+ return 0xf0;
+ case GITS_CIDR2:
+ return 0x05;
+ case GITS_CIDR3:
+ return 0xb1;
+ }
+
+ return 0;
+}
+
+static void its_free_itte(struct its_itte *itte)
+{
+ list_del(&itte->itte_list);
+ kfree(itte);
+}
+
+static int vits_handle_command(struct kvm *kvm, struct vgic_its *its,
+ u64 *its_cmd)
+{
+ return -ENODEV;
+}
+
+static unsigned long vgic_mmio_read_its_cbaser(struct kvm *kvm,
+ struct vgic_its *its,
+ gpa_t addr, unsigned int len)
+{
+ return extract_bytes(its->cbaser, addr & 7, len);
+}
+
+static void vgic_mmio_write_its_cbaser(struct kvm *kvm, struct vgic_its *its,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ /* When GITS_CTLR.Enable is 1, this register is RO. */
+ if (its->enabled)
+ return;
+
+ mutex_lock(&its->cmd_lock);
+ its->cbaser = update_64bit_reg(its->cbaser, addr & 7, len, val);
+ vgic_sanitise_its_baser(&its->cbaser);
+ its->creadr = 0;
+ /*
+ * CWRITER is architecturally UNKNOWN on reset, but we need to reset
+ * it to CREADR to make sure we start with an empty command buffer.
+ */
+ its->cwriter = its->creadr;
+ mutex_unlock(&its->cmd_lock);
+}
+
+#define ITS_CMD_BUFFER_SIZE(baser) ((((baser) & 0xff) + 1) << 12)
+
+/*
+ * By writing to CWRITER the guest announces new commands to be processed.
+ * To avoid any races in the first place, we take the its_cmd lock, which
+ * protects our ring buffer variables, so that there is only one user
+ * per ITS handling commands at a given time.
+ */
+static void vgic_mmio_write_its_cwriter(struct kvm *kvm, struct vgic_its *its,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ gpa_t cbaser;
+ u64 cmd_buf[4];
+ u32 reg;
+
+ if (!its)
+ return;
+
+ cbaser = CBASER_ADDRESS(its->cbaser);
+
+ reg = update_64bit_reg(its->cwriter & 0xfffe0, addr & 7, len, val);
+ reg &= 0xfffe0;
+ if (reg > ITS_CMD_BUFFER_SIZE(its->cbaser))
+ return;
+
+ mutex_lock(&its->cmd_lock);
+
+ its->cwriter = reg;
+
+ while (its->cwriter != its->creadr) {
+ int ret = kvm_read_guest(kvm, cbaser + its->creadr,
+ cmd_buf, 32);
+ if (ret) {
+ /*
+ * Gah, we are screwed. Either the guest programmed
+ * bogus values in CBASER or something else went
+ * wrong from which we cannot easily recover.
+ * Reset CWRITER to the command that we have finished
+ * processing and return.
+ */
+ its->cwriter = its->creadr;
+ break;
+ }
+ vits_handle_command(kvm, its, cmd_buf);
+
+ its->creadr += 32;
+ if (its->creadr == ITS_CMD_BUFFER_SIZE(its->cbaser))
+ its->creadr = 0;
+ }
+
+ mutex_unlock(&its->cmd_lock);
+}
+
+static unsigned long vgic_mmio_read_its_cwriter(struct kvm *kvm,
+ struct vgic_its *its,
+ gpa_t addr, unsigned int len)
+{
+ return extract_bytes(its->cwriter & 0xfffe0, addr & 0x7, len);
+}
+
+static unsigned long vgic_mmio_read_its_creadr(struct kvm *kvm,
+ struct vgic_its *its,
+ gpa_t addr, unsigned int len)
+{
+ return extract_bytes(its->creadr & 0xfffe0, addr & 0x7, len);
+}
+
+#define BASER_INDEX(addr) (((addr) / sizeof(u64)) & 0x7)
+static unsigned long vgic_mmio_read_its_baser(struct kvm *kvm,
+ struct vgic_its *its,
+ gpa_t addr, unsigned int len)
+{
+ u64 reg;
+
+ switch (BASER_INDEX(addr)) {
+ case 0:
+ reg = its->baser_device_table;
+ break;
+ case 1:
+ reg = its->baser_coll_table;
+ break;
+ default:
+ reg = 0;
+ break;
+ }
+
+ return extract_bytes(reg, addr & 7, len);
+}
+
+#define GITS_BASER_RO_MASK \
+ ((0x1fLL << GITS_BASER_ENTRY_SIZE_SHIFT) | \
+ (0x07LL << GITS_BASER_TYPE_SHIFT))
+static void vgic_mmio_write_its_baser(struct kvm *kvm,
+ struct vgic_its *its,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u64 reg, *regptr;
+ u64 entry_size, device_type;
+
+ /* When GITS_CTLR.Enable is 1, we ignore write accesses. */
+ if (its->enabled)
+ return;
+
+ switch (BASER_INDEX(addr)) {
+ case 0:
+ regptr = &its->baser_device_table;
+ entry_size = 8;
+ device_type = GITS_BASER_TYPE_DEVICE;
+ break;
+ case 1:
+ regptr = &its->baser_coll_table;
+ entry_size = 8;
+ device_type = GITS_BASER_TYPE_COLLECTION;
+ break;
+ default:
+ return;
+ }
+
+ reg = update_64bit_reg(*regptr, addr & 7, len, val);
+ reg &= ~GITS_BASER_RO_MASK;
+ reg |= (entry_size - 1) << GITS_BASER_ENTRY_SIZE_SHIFT;
+ reg |= device_type << GITS_BASER_TYPE_SHIFT;
+ vgic_sanitise_its_baser(®);
+
+ *regptr = reg;
+}
+
#define REGISTER_ITS_DESC(off, rd, wr, length, acc) \
{ \
.reg_offset = off, \
@@ -43,8 +327,8 @@
.its_write = wr, \
}
-static unsigned long its_mmio_read_raz(struct kvm *kvm, struct vgic_its *its,
- gpa_t addr, unsigned int len)
+unsigned long its_mmio_read_raz(struct kvm *kvm, struct vgic_its *its,
+ gpa_t addr, unsigned int len)
{
return 0;
}
@@ -57,28 +341,28 @@ static void its_mmio_write_wi(struct kvm *kvm, struct vgic_its *its,
struct vgic_register_region its_registers[] = {
REGISTER_ITS_DESC(GITS_CTLR,
- its_mmio_read_raz, its_mmio_write_wi, 4,
+ vgic_mmio_read_its_ctlr, vgic_mmio_write_its_ctlr, 4,
VGIC_ACCESS_32bit),
REGISTER_ITS_DESC(GITS_IIDR,
- its_mmio_read_raz, its_mmio_write_wi, 4,
+ vgic_mmio_read_its_iidr, its_mmio_write_wi, 4,
VGIC_ACCESS_32bit),
REGISTER_ITS_DESC(GITS_TYPER,
- its_mmio_read_raz, its_mmio_write_wi, 8,
+ vgic_mmio_read_its_typer, its_mmio_write_wi, 8,
VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
REGISTER_ITS_DESC(GITS_CBASER,
- its_mmio_read_raz, its_mmio_write_wi, 8,
+ vgic_mmio_read_its_cbaser, vgic_mmio_write_its_cbaser, 8,
VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
REGISTER_ITS_DESC(GITS_CWRITER,
- its_mmio_read_raz, its_mmio_write_wi, 8,
+ vgic_mmio_read_its_cwriter, vgic_mmio_write_its_cwriter, 8,
VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
REGISTER_ITS_DESC(GITS_CREADR,
- its_mmio_read_raz, its_mmio_write_wi, 8,
+ vgic_mmio_read_its_creadr, its_mmio_write_wi, 8,
VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
REGISTER_ITS_DESC(GITS_BASER,
- its_mmio_read_raz, its_mmio_write_wi, 0x40,
+ vgic_mmio_read_its_baser, vgic_mmio_write_its_baser, 0x40,
VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
REGISTER_ITS_DESC(GITS_IDREGS_BASE,
- its_mmio_read_raz, its_mmio_write_wi, 0x30,
+ vgic_mmio_read_its_idregs, its_mmio_write_wi, 0x30,
VGIC_ACCESS_32bit),
};
@@ -103,10 +387,40 @@ static int vits_register(struct kvm *kvm, struct vgic_its *its)
static void vits_destroy(struct kvm *kvm, struct vgic_its *its)
{
+ struct its_device *dev;
+ struct its_itte *itte;
+ struct list_head *dev_cur, *dev_temp;
+ struct list_head *cur, *temp;
+
+ /*
+ * We may end up here without the lists ever having been initialized.
+ * Check this and bail out early to avoid dereferencing a NULL pointer.
+ */
+ if (!its->device_list.next)
+ return;
+
+ mutex_lock(&its->its_lock);
+ list_for_each_safe(dev_cur, dev_temp, &its->device_list) {
+ dev = container_of(dev_cur, struct its_device, dev_list);
+ list_for_each_safe(cur, temp, &dev->itt_head) {
+ itte = (container_of(cur, struct its_itte, itte_list));
+ its_free_itte(itte);
+ }
+ list_del(dev_cur);
+ kfree(dev);
+ }
+
+ list_for_each_safe(cur, temp, &its->collection_list) {
+ list_del(cur);
+ kfree(container_of(cur, struct its_collection, coll_list));
+ }
+ mutex_unlock(&its->its_lock);
its->enabled = false;
}
+#define INITIAL_BASER_VALUE (GITS_BASER_WaWb | GITS_BASER_PAGE_SIZE_64K)
+
static int vgic_its_create(struct kvm_device *dev, u32 type)
{
struct vgic_its *its;
@@ -118,11 +432,20 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
if (!its)
return -ENOMEM;
+ mutex_init(&its->its_lock);
+ mutex_init(&its->cmd_lock);
+
its->vgic_its_base = VGIC_ADDR_UNDEF;
+ INIT_LIST_HEAD(&its->device_list);
+ INIT_LIST_HEAD(&its->collection_list);
+
dev->kvm->arch.vgic.has_its = true;
its->enabled = false;
+ its->baser_device_table = INITIAL_BASER_VALUE;
+ its->baser_coll_table = INITIAL_BASER_VALUE;
+
dev->private = its;
return 0;
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index 3a72308..da74d67 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -23,15 +23,15 @@
#include "vgic-mmio.h"
/* extract @num bytes at @offset bytes offset in data */
-static unsigned long extract_bytes(unsigned long data, unsigned int offset,
- unsigned int num)
+unsigned long extract_bytes(unsigned long data, unsigned int offset,
+ unsigned int num)
{
return (data >> (offset * 8)) & GENMASK_ULL(num * 8 - 1, 0);
}
/* allows updates of any half of a 64-bit register (or the whole thing) */
-static u64 update_64bit_reg(u64 reg, unsigned int offset, unsigned int len,
- unsigned long val)
+u64 update_64bit_reg(u64 reg, unsigned int offset, unsigned int len,
+ unsigned long val)
{
int lower = (offset & 4) * 8;
int upper = lower + 8 * len - 1;
@@ -239,6 +239,13 @@ static void vgic_sanitise_redist_baser(u64 *reg)
vgic_sanitise_outer_cacheability(reg, 56);
}
+void vgic_sanitise_its_baser(u64 *reg)
+{
+ vgic_sanitise_shareability(reg);
+ vgic_sanitise_inner_cacheability(reg, GITS_BASER_CACHEABILITY_SHIFT);
+ vgic_sanitise_outer_cacheability(reg, 53);
+}
+
#define PROPBASER_RES0_MASK 0xf8f0000000000060
#define PENDBASER_RES0_MASK 0xb8f000000000f07f
diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
index 6dfc2f0..f6fd662 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.h
+++ b/virt/kvm/arm/vgic/vgic-mmio.h
@@ -91,6 +91,12 @@ 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);
+
+u64 update_64bit_reg(u64 reg, unsigned int offset, unsigned int len,
+ unsigned long val);
+
unsigned long vgic_mmio_read_raz(struct kvm_vcpu *vcpu,
gpa_t addr, unsigned int len);
@@ -151,4 +157,8 @@ unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
unsigned int vgic_v3_init_dist_iodev(struct vgic_io_device *dev);
+#ifdef CONFIG_KVM_ARM_VGIC_V3
+void vgic_sanitise_its_baser(u64 *reg);
+#endif
+
#endif
--
2.8.2
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