[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Xen-devel] [PATCH v6 24/36] ARM: vITS: add command handling stub and MMIO emulation
Hi Andre,
On 04/07/2017 06:32 PM, Andre Przywara wrote:
Emulate the memory mapped ITS registers and provide a stub to introduce
the ITS command handling framework (but without actually emulating any
commands at this time).
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
xen/arch/arm/vgic-v3-its.c | 512 +++++++++++++++++++++++++++++++++++++++
xen/include/asm-arm/gic_v3_its.h | 3 +
2 files changed, 515 insertions(+)
diff --git a/xen/arch/arm/vgic-v3-its.c b/xen/arch/arm/vgic-v3-its.c
index 065ffe2..a171a3b 100644
--- a/xen/arch/arm/vgic-v3-its.c
+++ b/xen/arch/arm/vgic-v3-its.c
@@ -67,6 +67,9 @@ struct vits_itte
uint16_t pad;
};
+#define GITS_BASER_RO_MASK (GITS_BASER_TYPE_MASK | \
+ (31UL << GITS_BASER_ENTRY_SIZE_SHIFT))
+
int vgic_v3_its_init_domain(struct domain *d)
{
spin_lock_init(&d->arch.vgic.its_devices_lock);
@@ -80,6 +83,515 @@ void vgic_v3_its_free_domain(struct domain *d)
ASSERT(RB_EMPTY_ROOT(&d->arch.vgic.its_devices));
}
+/**************************************
+ * Functions that handle ITS commands *
+ **************************************/
+
+static uint64_t its_cmd_mask_field(uint64_t *its_cmd, unsigned int word,
+ unsigned int shift, unsigned int size)
+{
+ return (le64_to_cpu(its_cmd[word]) >> shift) & (BIT(size) - 1);
+}
+
+#define its_cmd_get_command(cmd) its_cmd_mask_field(cmd, 0, 0, 8)
+#define its_cmd_get_deviceid(cmd) its_cmd_mask_field(cmd, 0, 32, 32)
+#define its_cmd_get_size(cmd) its_cmd_mask_field(cmd, 1, 0, 5)
+#define its_cmd_get_id(cmd) its_cmd_mask_field(cmd, 1, 0, 32)
+#define its_cmd_get_physical_id(cmd) its_cmd_mask_field(cmd, 1, 32, 32)
+#define its_cmd_get_collection(cmd) its_cmd_mask_field(cmd, 2, 0, 16)
+#define its_cmd_get_target_addr(cmd) its_cmd_mask_field(cmd, 2, 16, 32)
+#define its_cmd_get_validbit(cmd) its_cmd_mask_field(cmd, 2, 63, 1)
+#define its_cmd_get_ittaddr(cmd) (its_cmd_mask_field(cmd, 2, 8, 44) <<
8)
+
+#define ITS_CMD_BUFFER_SIZE(baser) ((((baser) & 0xff) + 1) << 12)
+
+/*
+ * Requires the vcmd_lock to be held.
+ * TODO: Investigate whether we can be smarter here and don't need to hold
+ * the lock all of the time.
+ */
+static int vgic_its_handle_cmds(struct domain *d, struct virt_its *its)
+{
+ paddr_t addr = its->cbaser & GENMASK(51, 12);
+ uint64_t command[4];
+ uint64_t creadr = its->creadr;
+
+ ASSERT(spin_is_locked(&its->vcmd_lock));
+
+ if ( its->cwriter >= ITS_CMD_BUFFER_SIZE(its->cbaser) )
+ return -1;
+
+ while ( creadr != its->cwriter )
+ {
+ int ret;
+
+ ret = vgic_access_guest_memory(d, addr + creadr,
+ command, sizeof(command), false);
+ if ( ret )
+ return ret;
+
+ switch ( its_cmd_get_command(command) )
+ {
+ case GITS_CMD_SYNC:
+ /* We handle ITS commands synchronously, so we ignore SYNC. */
+ break;
+ default:
+ gdprintk(XENLOG_WARNING, "ITS: unhandled ITS command %lu\n",
+ its_cmd_get_command(command));
+ break;
+ }
+
+ creadr += ITS_CMD_SIZE;
+ if ( creadr == ITS_CMD_BUFFER_SIZE(its->cbaser) )
+ creadr = 0;
+ its->creadr = creadr; /* allow the guest to see the progress */
I hope you know that the compiler can decide to drop the temporary
variable for optimization? ;) So it may decide to write-back everytime
in its->creadr.
+
+ if ( ret )
+ gdprintk(XENLOG_WARNING,
+ "ITS: ITS command error %d while handling command %lu\n",
+ ret, its_cmd_get_command(command));
+ }
+
+ return 0;
+}
+
+/*****************************
+ * ITS registers read access *
+ *****************************/
+
+/* Identifying as an ARM IP, using "X" as the product ID. */
+#define GITS_IIDR_VALUE 0x5800034c
Do we need to request ARM to register this value? Preventing someone to
re-use it for another purpose in the future.
+
+static int vgic_v3_its_mmio_read(struct vcpu *v, mmio_info_t *info,
+ register_t *r, void *priv)
+{
+ struct virt_its *its = priv;
+ uint64_t reg;
+
+ switch ( info->gpa & 0xffff )
+ {
+ case VREG32(GITS_CTLR):
+ {
+ /*
+ * We try to avoid waiting for the command queue lock and report
+ * non-quiescent if that lock is already taken.
+ */
+ bool have_cmd_lock;
+
+ if ( info->dabt.size != DABT_WORD ) goto bad_width;
+
+ have_cmd_lock = spin_trylock(&its->vcmd_lock);
+ spin_lock(&its->its_lock);
+ if ( its->enabled )
+ reg = GITS_CTLR_ENABLE;
+ else
+ reg = 0;
+
+ if ( have_cmd_lock && its->cwriter == its->creadr )
+ reg |= GITS_CTLR_QUIESCENT;
+
+ spin_unlock(&its->its_lock);
+ if ( have_cmd_lock )
+ spin_unlock(&its->vcmd_lock);
+
+ *r = vgic_reg32_extract(reg, info);
+ break;
+ }
+ case VREG32(GITS_IIDR):
+ if ( info->dabt.size != DABT_WORD ) goto bad_width;
+ *r = vgic_reg32_extract(GITS_IIDR_VALUE, info);
+ break;
+ case VREG64(GITS_TYPER):
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+
+ reg = GITS_TYPER_PHYSICAL;
+ reg |= (sizeof(struct vits_itte) - 1) << GITS_TYPER_ITT_SIZE_SHIFT;
+ reg |= (its->intid_bits - 1) << GITS_TYPER_IDBITS_SHIFT;
+ reg |= (its->devid_bits - 1) << GITS_TYPER_DEVIDS_SHIFT;
+ *r = vgic_reg64_extract(reg, info);
+ break;
+ case 0x0018 ... 0x001c:
+ goto read_reserved;
+ case 0x0020 ... 0x003c:
+ goto read_impl_defined;
+ case 0x0040 ... 0x007c:
+ goto read_reserved;
+ case VREG64(GITS_CBASER):
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+ spin_lock(&its->its_lock);
+ *r = vgic_reg64_extract(its->cbaser, info);
+ spin_unlock(&its->its_lock);
+ break;
+ case VREG64(GITS_CWRITER):
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+
+ reg = its->cwriter;
+ *r = vgic_reg64_extract(reg, info);
+ break;
+ case VREG64(GITS_CREADR):
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+
+ reg = its->creadr;
+ *r = vgic_reg64_extract(reg, info);
+ break;
+ case 0x0098 ... 0x00fc:
+ goto read_reserved;
+ case VREG64(GITS_BASER0): /* device table */
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+ spin_lock(&its->its_lock);
+ *r = vgic_reg64_extract(its->baser_dev, info);
+ spin_unlock(&its->its_lock);
+ break;
+ case VREG64(GITS_BASER1): /* collection table */
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+ spin_lock(&its->its_lock);
+ *r = vgic_reg64_extract(its->baser_coll, info);
+ spin_unlock(&its->its_lock);
+ break;
+ case VRANGE64(GITS_BASER2, GITS_BASER7):
+ goto read_as_zero_64;
+ case 0x0140 ... 0xbffc:
+ goto read_reserved;
+ case 0xc000 ... 0xffcc:
+ goto read_impl_defined;
+ case 0xffd0 ... 0xffe4:
+ goto read_as_zero_64;
+ case VREG32(GITS_PIDR2):
+ if ( info->dabt.size != DABT_WORD ) goto bad_width;
+ *r = vgic_reg32_extract(GIC_PIDR2_ARCH_GICv3, info);
+ break;
+ case 0xffec ... 0xfffc:
+ goto read_as_zero_64;
Why don't you have a default here? You don't cover all the ranges
(basically all the end of reserved regions such as 0xfffc - 0xfffe ...).
For those accesses you will return 1 as it was handled.
So please add a default and switch all s ... e to VRANGE*.
+ }
+
+ return 1;
+
+read_as_zero_64:
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+ *r = 0;
+
+ return 1;
+
+read_impl_defined:
+ printk(XENLOG_G_DEBUG
+ "%pv: vGITS: RAZ on implementation defined register offset
%#04lx\n",
+ v, info->gpa & 0xffff);
+ *r = 0;
+ return 1;
+
+read_reserved:
+ printk(XENLOG_G_DEBUG
+ "%pv: vGITS: RAZ on reserved register offset %#04lx\n",
+ v, info->gpa & 0xffff);
+ *r = 0;
+ return 1;
+
+bad_width:
+ printk(XENLOG_G_ERR "vGIIS: bad read width %d r%d offset %#04lx\n",
+ info->dabt.size, info->dabt.reg, (unsigned long)info->gpa & 0xffff);
+ domain_crash_synchronous();
+
+ return 0;
+}
+
+/******************************
+ * ITS registers write access *
+ ******************************/
+
+static unsigned int its_baser_table_size(uint64_t baser)
+{
+ unsigned int ret, page_size[4] = {SZ_4K, SZ_16K, SZ_64K, SZ_64K};
+
+ ret = page_size[(baser >> GITS_BASER_PAGE_SIZE_SHIFT) & 3];
+
+ return ret * ((baser & GITS_BASER_SIZE_MASK) + 1);
+}
+
+static unsigned int its_baser_nr_entries(uint64_t baser)
+{
+ int entry_size = GITS_BASER_ENTRY_SIZE(baser);
You said you fixed this .... but it looks like not. So please
s/int/unsigned int/
+
+ return its_baser_table_size(baser) / entry_size;
+}
+
+/* Must be called with the ITS lock held. */
+static bool vgic_v3_verify_its_status(struct virt_its *its, bool status)
+{
+ ASSERT(spin_is_locked(&its->its_lock));
+
+ if ( !status )
+ return false;
+
+ if ( !(its->cbaser & GITS_VALID_BIT) ||
+ !(its->baser_dev & GITS_VALID_BIT) ||
+ !(its->baser_coll & GITS_VALID_BIT) )
+ {
+ printk(XENLOG_G_WARNING "d%d tried to enable ITS without having the tables
configured.\n",
+ its->d->domain_id);
+ return false;
+ }
+
+ return true;
+}
+
+static void sanitize_its_base_reg(uint64_t *reg)
+{
+ uint64_t r = *reg;
+
+ /* Avoid outer shareable. */
+ switch ( (r >> GITS_BASER_SHAREABILITY_SHIFT) & 0x03 )
+ {
+ case GIC_BASER_OuterShareable:
+ r = r & ~GITS_BASER_SHAREABILITY_MASK;
NIT r &= ~GITS...;
+ r |= GIC_BASER_InnerShareable << GITS_BASER_SHAREABILITY_SHIFT;
+ break;
+ default:
+ break;
+ }
+
+ /* Avoid any inner non-cacheable mapping. */
+ switch ( (r >> GITS_BASER_INNER_CACHEABILITY_SHIFT) & 0x07 )
+ {
+ case GIC_BASER_CACHE_nCnB:
+ case GIC_BASER_CACHE_nC:
+ r = r & ~GITS_BASER_INNER_CACHEABILITY_MASK;
Ditto.
+ r |= GIC_BASER_CACHE_RaWb << GITS_BASER_INNER_CACHEABILITY_SHIFT;
+ break;
+ default:
+ break;
+ }
+
+ /* Only allow non-cacheable or same-as-inner. */
+ switch ( (r >> GITS_BASER_OUTER_CACHEABILITY_SHIFT) & 0x07 )
+ {
+ case GIC_BASER_CACHE_SameAsInner:
+ case GIC_BASER_CACHE_nC:
+ break;
+ default:
+ r = r & ~GITS_BASER_OUTER_CACHEABILITY_MASK;
Ditto.
+ r |= GIC_BASER_CACHE_nC << GITS_BASER_OUTER_CACHEABILITY_SHIFT;
+ break;
+ }
+
+ *reg = r;
+}
+
+static int vgic_v3_its_mmio_write(struct vcpu *v, mmio_info_t *info,
+ register_t r, void *priv)
+{
+ struct domain *d = v->domain;
+ struct virt_its *its = priv;
+ uint64_t reg;
+ uint32_t reg32;
+
+ switch ( info->gpa & 0xffff )
+ {
+ case VREG32(GITS_CTLR):
+ {
+ uint32_t ctlr;
+
+ if ( info->dabt.size != DABT_WORD ) goto bad_width;
+
+ /*
+ * We need to take the vcmd_lock to prevent a guest from disabling
+ * the ITS while commands are still processed.
+ */
+ spin_lock(&its->vcmd_lock);
+ spin_lock(&its->its_lock);
+ ctlr = its->enabled ? GITS_CTLR_ENABLE : 0;
+ reg32 = ctlr;
+ vgic_reg32_update(®32, r, info);
+
+ if ( ctlr ^ reg32 )
+ its->enabled = vgic_v3_verify_its_status(its,
+ reg32 & GITS_CTLR_ENABLE);
+ spin_unlock(&its->its_lock);
+ spin_unlock(&its->vcmd_lock);
+ return 1;
+ }
+
+ case VREG32(GITS_IIDR):
+ goto write_ignore_32;
+ case VREG32(GITS_TYPER):
+ goto write_ignore_32;
+ case 0x0018 ... 0x001c:
Please correctly implement the range use VRANGE*.
+ goto write_reserved;
+ case 0x0020 ... 0x003c:
+ goto write_impl_defined;
+ case 0x0040 ... 0x007c:
+ goto write_reserved;
+ case VREG64(GITS_CBASER):
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+
+ spin_lock(&its->vcmd_lock);
Why do you need to take the command lock here? its->enabled will prevent
to modify cbaser to be overwritten.
+ spin_lock(&its->its_lock);
+ /* Changing base registers with the ITS enabled is UNPREDICTABLE. */
+ if ( its->enabled )
+ {
+ spin_unlock(&its->its_lock);
+ spin_unlock(&its->vcmd_lock);
+ gdprintk(XENLOG_WARNING,
+ "ITS: tried to change CBASER with the ITS enabled.\n");
+ return 1;
+ }
+
+ reg = its->cbaser;
+ vgic_reg64_update(®, r, info);
+ sanitize_its_base_reg(®);
+
+ its->cbaser = reg;
+ its->creadr = 0;
+ spin_unlock(&its->its_lock);
+ spin_unlock(&its->vcmd_lock);
+
+ return 1;
+
+ case VREG64(GITS_CWRITER):
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+
+ spin_lock(&its->vcmd_lock);
+ reg = its->cwriter & 0xfffe0;
Please explain this mask.
+ vgic_reg64_update(®, r, info);
+ its->cwriter = reg & 0xfffe0;
Ditto. You likely need a define for that.
+
+ if ( its->enabled )
So its->enabled is in this case protected by vcmd_lock and not its->lock
as other place, correct? If so, please document it.
+ {
+ int ret = vgic_its_handle_cmds(d, its);
I am not convinced of the usefulness of the temporary variable ret. You
could directly do:
if ( vgic_its_handle_cmds(...) )
printk(....)
+
+ if ( ret )
+ printk(XENLOG_G_WARNING "error handling ITS commands\n");
Again you likely want to print the domain id here. So I would it to
gdprintk.
+ }
+ spin_unlock(&its->vcmd_lock);
+
+ return 1;
+
+ case VREG64(GITS_CREADR):
+ goto write_ignore_64;
+
+ case 0x0098 ... 0x00fc:
+ goto write_reserved;
+ case VREG64(GITS_BASER0): /* device table */
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+
+ spin_lock(&its->its_lock);
+
+ /*
+ * Changing base registers with the ITS enabled is UNPREDICTABLE,
+ * we choose to ignore it, but warn.
+ */
+ if ( its->enabled )
+ {
+ spin_unlock(&its->its_lock);
+ gdprintk(XENLOG_WARNING, "ITS: tried to change BASER with the ITS
enabled.\n");
+
+ return 1;
+ }
+
+ reg = its->baser_dev;
+ vgic_reg64_update(®, r, info);
+
+ /* We don't support indirect tables for now. */
+ reg &= ~(GITS_BASER_RO_MASK | GITS_BASER_INDIRECT);
+ reg |= (sizeof(uint64_t) - 1) << GITS_BASER_ENTRY_SIZE_SHIFT;
+ reg |= GITS_BASER_TYPE_DEVICE << GITS_BASER_TYPE_SHIFT;
+ sanitize_its_base_reg(®);
+
+ if ( reg & GITS_VALID_BIT )
+ {
+ its->max_devices = its_baser_nr_entries(reg);
+ if ( its->max_devices > BIT(its->devid_bits) )
+ its->max_devices = BIT(its->devid_bits);
+ }
+ else
+ its->max_devices = 0;
+
+ its->baser_dev = reg;
+ spin_unlock(&its->its_lock);
+ return 1;
+ case VREG64(GITS_BASER1): /* collection table */
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+
+ spin_lock(&its->its_lock);
+ /*
+ * Changing base registers with the ITS enabled is UNPREDICTABLE,
+ * we choose to ignore it, but warn.
+ */
+ if ( its->enabled )
+ {
+ spin_unlock(&its->its_lock);
+ gdprintk(XENLOG_INFO, "ITS: tried to change BASER with the ITS
enabled.\n");
+ return 1;
+ }
+
+ reg = its->baser_coll;
+ vgic_reg64_update(®, r, info);
+ /* No indirect tables for the collection table. */
+ reg &= ~(GITS_BASER_RO_MASK | GITS_BASER_INDIRECT);
+ reg |= (sizeof(uint16_t) - 1) << GITS_BASER_ENTRY_SIZE_SHIFT;
+ reg |= GITS_BASER_TYPE_COLLECTION << GITS_BASER_TYPE_SHIFT;
+ sanitize_its_base_reg(®);
+
+ if ( reg & GITS_VALID_BIT )
+ its->max_collections = its_baser_nr_entries(reg);
+ else
+ its->max_collections = 0;
+ its->baser_coll = reg;
+ spin_unlock(&its->its_lock);
+ return 1;
+ case VRANGE64(GITS_BASER2, GITS_BASER7):
+ goto write_ignore_64;
+ case 0x0140 ... 0xbffc:
+ goto write_reserved;
+ case 0xc000 ... 0xffcc:
+ goto write_impl_defined;
+ case 0xffd0 ... 0xffe4: /* IMPDEF identification registers */
+ goto write_impl_defined;
+ case VREG32(GITS_PIDR2):
+ goto write_ignore_32;
+ case 0xffec ... 0xfffc: /* IMPDEF identification registers */
+ goto write_impl_defined;
+ default:
+ gdprintk(XENLOG_G_WARNING, "ITS: unhandled ITS register 0x%lx\n",
+ info->gpa & 0xffff);
+ return 0;
+ }
+
+ return 1;
+
+write_ignore_64:
+ if ( !vgic_reg64_check_access(info->dabt) ) goto bad_width;
+ return 1;
+
+write_ignore_32:
+ if ( info->dabt.size != DABT_WORD ) goto bad_width;
+ return 1;
+
+write_impl_defined:
+ printk(XENLOG_G_DEBUG
+ "%pv: vGITS: WI on implementation defined register offset %#04lx\n",
+ v, info->gpa & 0xffff);
+ return 1;
+
+write_reserved:
+ printk(XENLOG_G_DEBUG
+ "%pv: vGITS: WI on implementation defined register offset %#04lx\n",
+ v, info->gpa & 0xffff);
+ return 1;
+
+bad_width:
+ printk(XENLOG_G_ERR "vGITS: bad write width %d r%d offset %#08lx\n",
+ info->dabt.size, info->dabt.reg, (unsigned long)info->gpa & 0xffff);
+
+ domain_crash_synchronous();
+
+ return 0;
+}
+
+static const struct mmio_handler_ops vgic_its_mmio_handler = {
+ .read = vgic_v3_its_mmio_read,
+ .write = vgic_v3_its_mmio_write,
+};
+
/*
* Local variables:
* mode: C
diff --git a/xen/include/asm-arm/gic_v3_its.h b/xen/include/asm-arm/gic_v3_its.h
index 09c7117..ea574c4 100644
--- a/xen/include/asm-arm/gic_v3_its.h
+++ b/xen/include/asm-arm/gic_v3_its.h
@@ -35,6 +35,7 @@
#define GITS_BASER5 0x128
#define GITS_BASER6 0x130
#define GITS_BASER7 0x138
+#define GITS_PIDR2 GICR_PIDR2
/* Register bits */
#define GITS_VALID_BIT BIT(63)
@@ -57,6 +58,7 @@
#define GITS_TYPER_ITT_SIZE_MASK (0xfUL << GITS_TYPER_ITT_SIZE_SHIFT)
#define GITS_TYPER_ITT_SIZE(r) ((((r) & GITS_TYPER_ITT_SIZE_MASK) >> \
GITS_TYPER_ITT_SIZE_SHIFT) +
1)
+#define GITS_TYPER_PHYSICAL (1U << 0)
#define GITS_BASER_INDIRECT BIT(62)
#define GITS_BASER_INNER_CACHEABILITY_SHIFT 59
@@ -76,6 +78,7 @@
(((reg >> GITS_BASER_ENTRY_SIZE_SHIFT) & 0x1f) + 1)
#define GITS_BASER_SHAREABILITY_SHIFT 10
#define GITS_BASER_PAGE_SIZE_SHIFT 8
+#define GITS_BASER_SIZE_MASK 0xff
#define GITS_BASER_SHAREABILITY_MASK (0x3ULL <<
GITS_BASER_SHAREABILITY_SHIFT)
#define GITS_BASER_OUTER_CACHEABILITY_MASK (0x7ULL <<
GITS_BASER_OUTER_CACHEABILITY_SHIFT)
#define GITS_BASER_INNER_CACHEABILITY_MASK (0x7ULL <<
GITS_BASER_INNER_CACHEABILITY_SHIFT)
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel
|
