[PATCH 2/3] KVM: PPC: Book3S HV: XIVE: do not test the EQ flag validity when resetting

Cédric Le Goater
2019-05-20T07:15:41Z

When a CPU is hot-unplugged, the EQ is deconfigured using a zero size
and a zero address. In this case, there is no need to check the flag
and queue size validity. Move the checks after the queue reset code
section to fix CPU hot-unplug.

Reported-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Tested-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
arch/powerpc/kvm/book3s_xive_native.c | 36 +++++++++++++--------------
1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
index 796d86549cfe..3fdea6bf4e97 100644
--- a/arch/powerpc/kvm/book3s_xive_native.c
+++ b/arch/powerpc/kvm/book3s_xive_native.c
@@ -565,24 +565,6 @@ static int kvmppc_xive_native_set_queue_config(struct kvmppc_xive *xive,
__func__, server, priority, kvm_eq.flags,
kvm_eq.qshift, kvm_eq.qaddr, kvm_eq.qtoggle, kvm_eq.qindex);

- /*
- * sPAPR specifies a "Unconditional Notify (n) flag" for the
- * H_INT_SET_QUEUE_CONFIG hcall which forces notification
- * without using the coalescing mechanisms provided by the
- * XIVE END ESBs. This is required on KVM as notification
- * using the END ESBs is not supported.
- */
- if (kvm_eq.flags != KVM_XIVE_EQ_ALWAYS_NOTIFY) {
- pr_err("invalid flags %d\n", kvm_eq.flags);
- return -EINVAL;
- }
-
- rc = xive_native_validate_queue_size(kvm_eq.qshift);
- if (rc) {
- pr_err("invalid queue size %d\n", kvm_eq.qshift);
- return rc;
- }
-
/* reset queue and disable queueing */
if (!kvm_eq.qshift) {
q->guest_qaddr = 0;
@@ -604,6 +586,24 @@ static int kvmppc_xive_native_set_queue_config(struct kvmppc_xive *xive,
return 0;
}

+ /*
+ * sPAPR specifies a "Unconditional Notify (n) flag" for the
+ * H_INT_SET_QUEUE_CONFIG hcall which forces notification
+ * without using the coalescing mechanisms provided by the
+ * XIVE END ESBs. This is required on KVM as notification
+ * using the END ESBs is not supported.
+ */
+ if (kvm_eq.flags != KVM_XIVE_EQ_ALWAYS_NOTIFY) {
+ pr_err("invalid flags %d\n", kvm_eq.flags);
+ return -EINVAL;
+ }
+
+ rc = xive_native_validate_queue_size(kvm_eq.qshift);
+ if (rc) {
+ pr_err("invalid queue size %d\n", kvm_eq.qshift);
+ return rc;
+ }
+
if (kvm_eq.qaddr & ((1ull << kvm_eq.qshift) - 1)) {
pr_err("queue page is not aligned %llx/%llx\n", kvm_eq.qaddr,
1ull << kvm_eq.qshift);
--
2.20.1