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-rw-r--r--virt/kvm/arm/vgic/vgic-mmio.c41
-rw-r--r--virt/kvm/arm/vgic/vgic-mmio.h14
2 files changed, 34 insertions, 21 deletions
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index e18b30ddcdce..ebe1b9fa3c4d 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -453,17 +453,33 @@ struct vgic_io_device *kvm_to_vgic_iodev(const struct kvm_io_device *dev)
return container_of(dev, struct vgic_io_device, dev);
}
-static bool check_region(const struct vgic_register_region *region,
+static bool check_region(const struct kvm *kvm,
+ const struct vgic_register_region *region,
gpa_t addr, int len)
{
- if ((region->access_flags & VGIC_ACCESS_8bit) && len == 1)
- return true;
- if ((region->access_flags & VGIC_ACCESS_32bit) &&
- len == sizeof(u32) && !(addr & 3))
- return true;
- if ((region->access_flags & VGIC_ACCESS_64bit) &&
- len == sizeof(u64) && !(addr & 7))
- return true;
+ int flags, nr_irqs = kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
+
+ switch (len) {
+ case sizeof(u8):
+ flags = VGIC_ACCESS_8bit;
+ break;
+ case sizeof(u32):
+ flags = VGIC_ACCESS_32bit;
+ break;
+ case sizeof(u64):
+ flags = VGIC_ACCESS_64bit;
+ break;
+ default:
+ return false;
+ }
+
+ if ((region->access_flags & flags) && IS_ALIGNED(addr, len)) {
+ if (!region->bits_per_irq)
+ return true;
+
+ /* Do we access a non-allocated IRQ? */
+ return VGIC_ADDR_TO_INTID(addr, region->bits_per_irq) < nr_irqs;
+ }
return false;
}
@@ -477,7 +493,7 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
addr - iodev->base_addr);
- if (!region || !check_region(region, addr, len)) {
+ if (!region || !check_region(vcpu->kvm, region, addr, len)) {
memset(val, 0, len);
return 0;
}
@@ -510,10 +526,7 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
addr - iodev->base_addr);
- if (!region)
- return 0;
-
- if (!check_region(region, addr, len))
+ if (!region || !check_region(vcpu->kvm, region, addr, len))
return 0;
switch (iodev->iodev_type) {
diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
index 4c34d39d44a0..84961b4e4422 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.h
+++ b/virt/kvm/arm/vgic/vgic-mmio.h
@@ -50,15 +50,15 @@ extern struct kvm_io_device_ops kvm_io_gic_ops;
#define VGIC_ADDR_IRQ_MASK(bits) (((bits) * 1024 / 8) - 1)
/*
- * (addr & mask) gives us the byte offset for the INT ID, so we want to
- * divide this with 'bytes per irq' to get the INT ID, which is given
- * by '(bits) / 8'. But we do this with fixed-point-arithmetic and
- * take advantage of the fact that division by a fraction equals
- * multiplication with the inverted fraction, and scale up both the
- * numerator and denominator with 8 to support at most 64 bits per IRQ:
+ * (addr & mask) gives us the _byte_ offset for the INT ID.
+ * We multiply this by 8 the get the _bit_ offset, then divide this by
+ * the number of bits to learn the actual INT ID.
+ * But instead of a division (which requires a "long long div" implementation),
+ * we shift by the binary logarithm of <bits>.
+ * This assumes that <bits> is a power of two.
*/
#define VGIC_ADDR_TO_INTID(addr, bits) (((addr) & VGIC_ADDR_IRQ_MASK(bits)) * \
- 64 / (bits) / 8)
+ 8 >> ilog2(bits))
/*
* Some VGIC registers store per-IRQ information, with a different number