A read to a write only register is unknown. Use a memorable value to
differentiate from an actual RAZ register.
Signed-off-by: Julien Grall <julien.gr...@citrix.com>
Acked-by: Ian Campbell <ian.campb...@citrix.com>
---
Changes in v2:
- Add Ian's acked-by
---
xen/arch/arm/vgic-v3.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index c68afdb..44e926a 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -217,12 +217,12 @@ static int __vgic_v3_rdistr_rd_mmio_read(struct vcpu *v,
mmio_info_t *info,
goto read_impl_defined;
case VREG64(GICR_SETLPIR):
- /* WO. Read as zero */
- goto read_as_zero_64;
+ /* WO. Read unknown */
+ goto read_unknown;
case VREG64(GICR_CLRLPIR):
- /* WO. Read as zero */
- goto read_as_zero_64;
+ /* WO. Read unknown */
+ goto read_unknown;
case 0x0050:
goto read_reserved;
@@ -239,15 +239,15 @@ static int __vgic_v3_rdistr_rd_mmio_read(struct vcpu *v,
mmio_info_t *info,
goto read_reserved;
case VREG64(GICR_INVLPIR):
- /* WO. Read as zero */
- goto read_as_zero_64;
+ /* WO. Read unknown */
+ goto read_unknown;
case 0x00A8:
goto read_reserved;
case VREG64(GICR_INVALLR):
- /* WO. Read as zero */
- goto read_as_zero_64;
+ /* WO. Read unknown */
+ goto read_unknown;
case 0x00B8:
goto read_reserved;
@@ -324,6 +324,10 @@ read_reserved:
v, gicr_reg);
*r = 0;
return 1;
+
+read_unknown:
+ *r = vgic_reg64_extract(0xdeadbeafdeadbeaf, info);
+ return 1;
}
static int __vgic_v3_rdistr_rd_mmio_write(struct vcpu *v, mmio_info_t *info,
--
2.1.4
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