KVM: arm64: Handle AIDR_EL1 and REVIDR_EL1 in host for protected VMs

Since commit 17efc1acee62 ("arm64: Expose AIDR_EL1 via sysfs"), AIDR_EL1
is read early during boot. Therefore, a guest running as a protected VM
will fail to boot because when it attempts to access AIDR_EL1, access to
that register is restricted in pKVM for protected guests.

Similar to how MIDR_EL1 is handled by the host for protected VMs, let
the host handle accesses to AIDR_EL1 as well as REVIDR_EL1. However note
that, unlike MIDR_EL1, AIDR_EL1 and REVIDR_EL1 are trapped by
HCR_EL2.TID1. Therefore, explicitly mark them as handled by the host for
protected VMs. TID1 is always set in pKVM, because it needs to restrict
access to SMIDR_EL1, which is also trapped by that bit.

Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20250807120133.871892-2-tabba@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
index 1ddd9ed3cbb3a9d057c1afc9441b12a57f61539b..bbd60013cf9e98ecb32d20abd3ff6334d3dfa8f8 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/sys_regs.c
+++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
@@ -372,6 +372,9 @@ static const struct sys_reg_desc pvm_sys_reg_descs[] = {
 
        /* Debug and Trace Registers are restricted. */
 
+       /* Group 1 ID registers */
+       HOST_HANDLED(SYS_REVIDR_EL1),
+
        /* AArch64 mappings of the AArch32 ID registers */
        /* CRm=1 */
        AARCH32(SYS_ID_PFR0_EL1),
@@ -460,6 +463,7 @@ static const struct sys_reg_desc pvm_sys_reg_descs[] = {
 
        HOST_HANDLED(SYS_CCSIDR_EL1),
        HOST_HANDLED(SYS_CLIDR_EL1),
+       HOST_HANDLED(SYS_AIDR_EL1),
        HOST_HANDLED(SYS_CSSELR_EL1),
        HOST_HANDLED(SYS_CTR_EL0),