Commit eaa43934 authored by Fuad Tabba's avatar Fuad Tabba Committed by Oliver Upton
Browse files

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



Since commit 17efc1ac ("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: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarFuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20250807120133.871892-2-tabba@google.com


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 700d6868

arch/arm64/kvm/hyp/nvhe/sys_regs.c

+4 −0
Original line number Diff line number Diff line
@@ -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),