[PATCH v6 11/24] KVM: arm64: vgic-its: Interpret MAPD Size field and check related errors

Eric Auger
2017-05-04T11:44:31Z

Up to now the MAPD's ITT size field has been ignored. It encodes
the number of eventid bit minus 1. It should be used to check
the eventid when a MAPTI command is issued on a device. Let's
store the number of eventid bits in the its_device and do the
check on MAPTI. Also make sure the ITT size field does
not exceed the GITS_TYPER IDBITS field.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>

---
v5 -> v6:
- add Christoffer's R-b
- rename nb_eventid_bits into num_eventid_bits

v4 -> v5:
- its_cmd_get_size macro now returns the actual number of eventid bits
- use GIC_ENCODE_SZ macro to encode ID_bits

v3 -> v4:
- VITS_TYPER_IDBITS set to 16 to be homogeneous with VITS_ESZ definition
and correct users
- nb_eventid_bits correspond to the actual number of eventid bits
---
include/linux/irqchip/arm-gic-v3.h | 2 ++
virt/kvm/arm/vgic/vgic-its.c | 15 ++++++++++++++-
2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index 59f1abd..9519c7b 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -346,9 +346,11 @@
#define E_ITS_INT_UNMAPPED_INTERRUPT 0x010307
#define E_ITS_CLEAR_UNMAPPED_INTERRUPT 0x010507
#define E_ITS_MAPD_DEVICE_OOR 0x010801
+#define E_ITS_MAPD_ITTSIZE_OOR 0x010802
#define E_ITS_MAPC_PROCNUM_OOR 0x010902
#define E_ITS_MAPC_COLLECTION_OOR 0x010903
#define E_ITS_MAPTI_UNMAPPED_DEVICE 0x010a04
+#define E_ITS_MAPTI_ID_OOR 0x010a05
#define E_ITS_MAPTI_PHYSICALID_OOR 0x010a06
#define E_ITS_INV_UNMAPPED_INTERRUPT 0x010c07
#define E_ITS_INVALL_UNMAPPED_COLLECTION 0x010d09
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 072efbd..06e01d1 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -105,6 +105,7 @@ struct its_device {

/* the head for the list of ITTEs */
struct list_head itt_head;
+ u32 num_eventid_bits;
u32 device_id;
};

@@ -201,6 +202,8 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 device_id,

#define GIC_LPI_OFFSET 8192

+#define VITS_TYPER_IDBITS 16
+
/*
* Finds and returns a collection in the ITS collection table.
* Must be called with the its_lock mutex held.
@@ -401,7 +404,7 @@ static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
* DevBits low - as least for the time being.
*/
reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
- reg |= 0x0f << GITS_TYPER_IDBITS_SHIFT;
+ reg |= GIC_ENCODE_SZ(VITS_TYPER_IDBITS, 5) << GITS_TYPER_IDBITS_SHIFT;
reg |= GIC_ENCODE_SZ(abi->ite_esz, 4) << GITS_TYPER_ITT_ENTRY_SIZE_SHIFT;

return extract_bytes(reg, addr & 7, len);
@@ -569,6 +572,7 @@ static u64 its_cmd_mask_field(u64 *its_cmd, int word, int shift, int size)

#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) + 1)
#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)
@@ -759,6 +763,9 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its,
if (!device)
return E_ITS_MAPTI_UNMAPPED_DEVICE;

+ if (event_id >= BIT_ULL(device->num_eventid_bits))
+ return E_ITS_MAPTI_ID_OOR;
+
if (its_cmd_get_command(its_cmd) == GITS_CMD_MAPTI)
lpi_nr = its_cmd_get_physical_id(its_cmd);
else
@@ -839,11 +846,15 @@ static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct vgic_its *its,
{
u32 device_id = its_cmd_get_deviceid(its_cmd);
bool valid = its_cmd_get_validbit(its_cmd);
+ u8 num_eventid_bits = its_cmd_get_size(its_cmd);
struct its_device *device;

if (!vgic_its_check_id(its, its->baser_device_table, device_id))
return E_ITS_MAPD_DEVICE_OOR;

+ if (valid && num_eventid_bits > VITS_TYPER_IDBITS)
+ return E_ITS_MAPD_ITTSIZE_OOR;
+
device = find_its_device(its, device_id);

/*
@@ -866,6 +877,8 @@ static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct vgic_its *its,
return -ENOMEM;

device->device_id = device_id;
+ device->num_eventid_bits = num_eventid_bits;
+
INIT_LIST_HEAD(&device->itt_head);

list_add_tail(&device->dev_list, &its->device_list);
--
2.5.5