[PATCH 1/3] KVM: arm64: Make ID_PFR1_EL1.GIC writable

[Marc Zyngier]

Similarly to ID_AA64PFR0_EL1.GIC, relax ID_PFR1_EL1.GIC to be writable.

Fixes: 5cb57a1aff755 ("KVM: arm64: Zero ID_AA64PFR0_EL1.GIC when no GICv3 is presented to the guest")
Reported-by: Peter Maydell <peter.maydell at linaro.org>
Signed-off-by: Marc Zyngier <maz at kernel.org>
Cc: stable at vger.kernel.org
---
 arch/arm64/kvm/sys_regs.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b29f72478a50d..73dcefe51a3e7 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2528,6 +2528,12 @@ static bool bad_redir_trap(struct kvm_vcpu *vcpu,
 	.val = mask,				\
 }
 
+#define AA32_ID_WRITABLE(name, mask) {		\
+	ID_DESC(name),				\
+	.visibility = aa32_id_visibility,	\
+	.val = mask,				\
+}
+
 /* sys_reg_desc initialiser for cpufeature ID registers that need filtering */
 #define ID_FILTERED(sysreg, name, mask) {	\
 	ID_DESC(sysreg),				\
@@ -3040,7 +3046,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	/* AArch64 mappings of the AArch32 ID registers */
 	/* CRm=1 */
 	AA32_ID_SANITISED(ID_PFR0_EL1),
-	AA32_ID_SANITISED(ID_PFR1_EL1),
+	AA32_ID_WRITABLE(ID_PFR1_EL1, ID_PFR1_EL1_GIC),
 	{ SYS_DESC(SYS_ID_DFR0_EL1),
 	  .access = access_id_reg,
 	  .get_user = get_id_reg,
-- 
2.47.3