[PATCH v3 05/19] KVM: arm64: ITS: Implement vgic_its_has_attr_regs and attr_regs_access
From: andre.przywara@arm.com (Andre Przywara)
Date: 2017-03-20 18:13:18
Also in:
kvm, kvmarm
Hi Eric, On 06/03/17 11:34, Eric Auger wrote:
quoted hunk ↗ jump to hunk
This patch implements vgic_its_has_attr_regs and vgic_its_attr_regs_access upon the MMIO framework. VGIC ITS KVM device KVM_DEV_ARM_VGIC_GRP_ITS_REGS group becomes functional. At least GITS_CREADR requires to differentiate a guest write action from a user access. As such let's introduce a new uaccess_its_write vgic_register_region callback. Signed-off-by: Eric Auger <eric.auger@redhat.com> --- virt/kvm/arm/vgic/vgic-its.c | 74 ++++++++++++++++++++++++++++++++++++------- virt/kvm/arm/vgic/vgic-mmio.h | 9 ++++-- 2 files changed, 69 insertions(+), 14 deletions(-)diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index 43bb17e..e9c8f9f 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c@@ -1287,13 +1287,14 @@ static void vgic_mmio_write_its_baser(struct kvm *kvm, *regptr = reg; } -#define REGISTER_ITS_DESC(off, rd, wr, length, acc) \ +#define REGISTER_ITS_DESC(off, rd, wr, uwr, length, acc) \ { \ .reg_offset = off, \ .len = length, \ .access_flags = acc, \ .its_read = rd, \ .its_write = wr, \ + .uaccess_its_write = uwr, \
I was wondering if it would create less churn to keep this definition here (with .uaccess_its_write automatically becoming NULL), and then either open-code the one special case below or provide a second wrapper macro. But I guess either way is not really nice, so we could go with this approach here as well.
quoted hunk ↗ jump to hunk
} static void its_mmio_write_wi(struct kvm *kvm, struct vgic_its *its,@@ -1304,28 +1305,28 @@ static void its_mmio_write_wi(struct kvm *kvm, struct vgic_its *its, static struct vgic_register_region its_registers[] = { REGISTER_ITS_DESC(GITS_CTLR, - vgic_mmio_read_its_ctlr, vgic_mmio_write_its_ctlr, 4, + vgic_mmio_read_its_ctlr, vgic_mmio_write_its_ctlr, NULL, 4, VGIC_ACCESS_32bit), REGISTER_ITS_DESC(GITS_IIDR, - vgic_mmio_read_its_iidr, its_mmio_write_wi, 4, + vgic_mmio_read_its_iidr, its_mmio_write_wi, NULL, 4, VGIC_ACCESS_32bit), REGISTER_ITS_DESC(GITS_TYPER, - vgic_mmio_read_its_typer, its_mmio_write_wi, 8, + vgic_mmio_read_its_typer, its_mmio_write_wi, NULL, 8, VGIC_ACCESS_64bit | VGIC_ACCESS_32bit), REGISTER_ITS_DESC(GITS_CBASER, - vgic_mmio_read_its_cbaser, vgic_mmio_write_its_cbaser, 8, + vgic_mmio_read_its_cbaser, vgic_mmio_write_its_cbaser, NULL, 8, VGIC_ACCESS_64bit | VGIC_ACCESS_32bit), REGISTER_ITS_DESC(GITS_CWRITER, - vgic_mmio_read_its_cwriter, vgic_mmio_write_its_cwriter, 8, - VGIC_ACCESS_64bit | VGIC_ACCESS_32bit), + vgic_mmio_read_its_cwriter, vgic_mmio_write_its_cwriter, NULL, + 8, VGIC_ACCESS_64bit | VGIC_ACCESS_32bit), REGISTER_ITS_DESC(GITS_CREADR, - vgic_mmio_read_its_creadr, its_mmio_write_wi, 8, + vgic_mmio_read_its_creadr, its_mmio_write_wi, NULL, 8, VGIC_ACCESS_64bit | VGIC_ACCESS_32bit), REGISTER_ITS_DESC(GITS_BASER, - vgic_mmio_read_its_baser, vgic_mmio_write_its_baser, 0x40, + vgic_mmio_read_its_baser, vgic_mmio_write_its_baser, NULL, 0x40, VGIC_ACCESS_64bit | VGIC_ACCESS_32bit), REGISTER_ITS_DESC(GITS_IDREGS_BASE, - vgic_mmio_read_its_idregs, its_mmio_write_wi, 0x30, + vgic_mmio_read_its_idregs, its_mmio_write_wi, NULL, 0x30, VGIC_ACCESS_32bit), };@@ -1448,14 +1449,63 @@ static void vgic_its_destroy(struct kvm_device *kvm_dev) int vgic_its_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr) { - return -ENXIO; + const struct vgic_register_region *region; + struct vgic_io_device iodev = { + .regions = its_registers, + .nr_regions = ARRAY_SIZE(its_registers), + }; + gpa_t offset; + + offset = attr->attr;
Those two can be on one line. But actually why not just put attr->attr below and save that variable at all?
+ + region = vgic_find_mmio_region(iodev.regions, + iodev.nr_regions, + offset); + if (!region) + return -ENXIO;
Nit: empty line here?
+ return 0;
}
int vgic_its_attr_regs_access(struct kvm_device *dev,
struct kvm_device_attr *attr,
u64 *reg, bool is_write)
{
- return -ENXIO;
+ const struct vgic_register_region *region;
+ struct vgic_io_device iodev = {
+ .regions = its_registers,
+ .nr_regions = ARRAY_SIZE(its_registers),
+ };
+ struct vgic_its *its = dev->private;
+ gpa_t addr, offset;
+ unsigned int len;
+
+ if (IS_VGIC_ADDR_UNDEF(its->vgic_its_base))
+ return -ENXIO;
+
+ offset = attr->attr;
+ if (offset & 0x7)
+ return -EINVAL;Isn't this still breaking IIDR reads (a 32-bit register at offset 0x4)?
+ + addr = its->vgic_its_base + offset; + + region = vgic_find_mmio_region(iodev.regions, + iodev.nr_regions, + offset); + if (!region) + return -ENXIO; + + len = region->access_flags & VGIC_ACCESS_64bit ? 8 : 4;
Can you add a comment that states that we only support full register accesses via this interface (deviating from the spec which allows split accesses to 64-bit registers)? I think that's mentioned somewhere else (Documentation/...), but it avoids confusion for the casual reader here. Also I am wondering if that way of using the pointer here for both 32- and 64-bit registers breaks on big endian? Or is it specified somewhere that this interface uses LE only? The rest looks fine, thanks! Cheers, Andre.
quoted hunk ↗ jump to hunk
+ if (is_write) { + if (region->uaccess_its_write) + region->uaccess_its_write(dev->kvm, its, addr, + len, *reg); + else + region->its_write(dev->kvm, its, addr, len, *reg); + } else { + *reg = region->its_read(dev->kvm, its, addr, len); + } + return 0; } static int vgic_its_has_attr(struct kvm_device *dev,diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h index 055ad42..ad8a585 100644 --- a/virt/kvm/arm/vgic/vgic-mmio.h +++ b/virt/kvm/arm/vgic/vgic-mmio.h@@ -36,8 +36,13 @@ struct vgic_register_region { }; unsigned long (*uaccess_read)(struct kvm_vcpu *vcpu, gpa_t addr, unsigned int len); - void (*uaccess_write)(struct kvm_vcpu *vcpu, gpa_t addr, - unsigned int len, unsigned long val); + union { + void (*uaccess_write)(struct kvm_vcpu *vcpu, gpa_t addr, + unsigned int len, unsigned long val); + void (*uaccess_its_write)(struct kvm *kvm, struct vgic_its *its, + gpa_t addr, unsigned int len, + unsigned long val); + }; }; extern struct kvm_io_device_ops kvm_io_gic_ops;