diff mbox series

[32/56] KVM: arm64/sve: sys_regs: Demote redundant vcpu_has_sve() checks to WARNs

Message ID 20190503124427.190206-33-marc.zyngier@arm.com (mailing list archive)
State New, archived
Headers show
Series [GIT,PULL] KVM/arm updates for 5.2 | expand

Commit Message

Marc Zyngier May 3, 2019, 12:44 p.m. UTC 
From: Dave Martin <Dave.Martin@arm.com>

Because of the logic in kvm_arm_sys_reg_{get,set}_reg() and
sve_id_visibility(), we should never call
{get,set}_id_aa64zfr0_el1() for a vcpu where !vcpu_has_sve(vcpu).

To avoid the code giving the impression that it is valid for these
functions to be called in this situation, and to help the compiler
make the right optimisation decisions, this patch adds WARN_ON()
for these cases.

Given the way the logic is spread out, this seems preferable to
dropping the checks altogether.

Suggested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/sys_regs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 09e9b0625911..7046c7686321 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1144,7 +1144,7 @@  static int get_id_aa64zfr0_el1(struct kvm_vcpu *vcpu,
 {
 	u64 val;
 
-	if (!vcpu_has_sve(vcpu))
+	if (WARN_ON(!vcpu_has_sve(vcpu)))
 		return -ENOENT;
 
 	val = guest_id_aa64zfr0_el1(vcpu);
@@ -1159,7 +1159,7 @@  static int set_id_aa64zfr0_el1(struct kvm_vcpu *vcpu,
 	int err;
 	u64 val;
 
-	if (!vcpu_has_sve(vcpu))
+	if (WARN_ON(!vcpu_has_sve(vcpu)))
 		return -ENOENT;
 
 	err = reg_from_user(&val, uaddr, id);