When running on a system with a GICv3, we currenly don't allow the guest
to access the system register interface of the GICv3. We do this by
clearing the ICC_SRE_EL2.Enable, which causes all guest accesses to
ICC_SRE_EL1 to trap to EL2 and causes all guest accesses to other ICC_
registers to cause an undefined exception in the guest.
However, we currently don't handle the trap of guest accesses to
ICC_SRE_EL1 and will spill out a warning. The trap just needs to handle
the access as RAZ/WI, and a guest that tries to prod this register and
set ICC_SRE_EL1.SRE=1, must read back the value (which Linux already
does) to see if it succeeded, and will thus observe that ICC_SRE_EL1.SRE
was not set.
Add the simple trap handler in the sorted table of the system registers.
Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
---
arch/arm64/kvm/sys_regs.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 4cc3b71..8f81945 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -424,6 +424,11 @@ static const struct sys_reg_desc sys_reg_descs[] = {
/* VBAR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b0000), Op2(0b000),
NULL, reset_val, VBAR_EL1, 0 },
+
+ /* ICC_SRE_EL1 */
+ { Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b1100), Op2(0b101),
+ trap_raz_wi },
+
/* CONTEXTIDR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1101), CRm(0b0000), Op2(0b001),
access_vm_reg, reset_val, CONTEXTIDR_EL1, 0 },
--
2.1.2.330.g565301e.dirty
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