[PATCH v4 1/6] KVM: arm64: Correctly treat writes to OSLSR_EL1 as undefined

[Oliver Upton]

Any valid implementation of the architecture should generate an
undefined exception for writes to a read-only register, such as
OSLSR_EL1. Nonetheless, the KVM handler actually implements write-ignore
behavior.

Align the trap handler for OSLSR_EL1 with hardware behavior. If such a
write ever traps to EL2, inject an undef into the guest and print a
warning.

Reviewed-by: Reiji Watanabe <reijiw at google.com>
Signed-off-by: Oliver Upton <oupton at google.com>
---
 arch/arm64/kvm/sys_regs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index e3ec1a44f94d..11b4212c2036 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -292,7 +292,7 @@ static bool trap_oslsr_el1(struct kvm_vcpu *vcpu,
 			   const struct sys_reg_desc *r)
 {
 	if (p->is_write) {
-		return ignore_write(vcpu, p);
+		return write_to_read_only(vcpu, p, r);
 	} else {
 		p->regval = (1 << 3);
 		return true;
-- 
2.34.1.173.g76aa8bc2d0-goog