[PATCH v7 08/24] KVM: arm64: vgic-its: Implement vgic_mmio_uaccess_write_its_creadr

Eric Auger
2017-05-06T15:22:25Z

GITS_CREADR needs to be restored so let's implement the associated
uaccess_write_its callback. The write only is allowed if the its
is disabled.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>

---
v6 -> v7:
- added Marc's A-b
- discard the stalled bit if set
- remove the alignment check as cmd_offset is [19:5] of the offset
and bits [4:0] are 0
- added Christoffer R-b

v5 -> v6:
- remove usage of update_64bit_reg and check alignment of cmd offset

v4 -> v5:
- keep Stalled bit
- vgic_mmio_uaccess_write_its_creadr can now return an error

v3 -> v4:
- REGISTER_ITS_DESC_UACCESS now introduced in this patch
- we now check the its is disabled
---
virt/kvm/arm/vgic/vgic-its.c | 42 ++++++++++++++++++++++++++++++++++++++++--
1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index fd2660d..bf3ff09 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1213,6 +1213,33 @@ static unsigned long vgic_mmio_read_its_creadr(struct kvm *kvm,
return extract_bytes(its->creadr, addr & 0x7, len);
}

+static int vgic_mmio_uaccess_write_its_creadr(struct kvm *kvm,
+ struct vgic_its *its,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 cmd_offset;
+ int ret = 0;
+
+ mutex_lock(&its->cmd_lock);
+
+ if (its->enabled) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ cmd_offset = ITS_CMD_OFFSET(val);
+ if (cmd_offset >= ITS_CMD_BUFFER_SIZE(its->cbaser)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ its->creadr = cmd_offset;
+out:
+ mutex_unlock(&its->cmd_lock);
+ return ret;
+}
+
#define BASER_INDEX(addr) (((addr) / sizeof(u64)) & 0x7)
static unsigned long vgic_mmio_read_its_baser(struct kvm *kvm,
struct vgic_its *its,
@@ -1317,6 +1344,16 @@ static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
.its_write = wr, \
}

+#define REGISTER_ITS_DESC_UACCESS(off, rd, wr, uwr, length, acc)\
+{ \
+ .reg_offset = off, \
+ .len = length, \
+ .access_flags = acc, \
+ .its_read = rd, \
+ .its_write = wr, \
+ .uaccess_its_write = uwr, \
+}
+
static void its_mmio_write_wi(struct kvm *kvm, struct vgic_its *its,
gpa_t addr, unsigned int len, unsigned long val)
{
@@ -1339,8 +1376,9 @@ static struct vgic_register_region its_registers[] = {
REGISTER_ITS_DESC(GITS_CWRITER,
vgic_mmio_read_its_cwriter, vgic_mmio_write_its_cwriter, 8,
VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
- REGISTER_ITS_DESC(GITS_CREADR,
- vgic_mmio_read_its_creadr, its_mmio_write_wi, 8,
+ REGISTER_ITS_DESC_UACCESS(GITS_CREADR,
+ vgic_mmio_read_its_creadr, its_mmio_write_wi,
+ vgic_mmio_uaccess_write_its_creadr, 8,
VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
REGISTER_ITS_DESC(GITS_BASER,
vgic_mmio_read_its_baser, vgic_mmio_write_its_baser, 0x40,
--
2.5.5