[RFC PATCH v3 10/27] KVM: SVM: Add avic_ipiv_is_soft_disabled() as a wrapper around enable_ipiv

[Naveen N Rao (AMD)]

enable_ipiv is used to disable AVIC IPI virtualization in software to
address hardware errata related to IPI acceleration, or because the user
chose to disable it manually through a module parameter. In either case,
AVIC IPIv itself is available in hardware and AVIC requires setup of
related data structures. To distinguish this from Secure AVIC mode which
completely lacks support for IPIv, add a helper to clarify the true
nature of this knob, which is to soft-disable IPIv.

Signed-off-by: Naveen N Rao (AMD) <naveen@xxxxxxxxxx>
---
 arch/x86/kvm/svm/avic.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 9b4d3a10198b..c9e375c5a9c1 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -67,6 +67,15 @@ static_assert(__AVIC_GATAG(AVIC_VM_ID_MASK, AVIC_VCPU_IDX_MASK) == -1u);
 
 #define AVIC_AUTO_MODE -1
 
+/*
+ * IPIv is supported, but software disabled due to erratum, or because
+ * the user turned it off through the module parameter.
+ */
+static bool avic_ipiv_is_soft_disabled(void)
+{
+	return !enable_ipiv;
+}
+
 static int avic_param_set(const char *val, const struct kernel_param *kp)
 {
 	if (val && sysfs_streq(val, "auto")) {
@@ -1092,7 +1101,7 @@ static void __avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu,
 	 * Keep the APIC ID up-to-date in the entry to minimize the chances of
 	 * things going sideways if hardware peeks at the ID.
 	 */
-	if (!enable_ipiv)
+	if (avic_ipiv_is_soft_disabled())
 		entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
 
 	WRITE_ONCE(kvm_svm->avic_physical_id_table[vcpu->vcpu_id], entry);
@@ -1150,7 +1159,7 @@ static void __avic_vcpu_put(struct kvm_vcpu *vcpu, enum avic_vcpu_action action)
 	 */
 	entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
 
-	if (enable_ipiv)
+	if (!avic_ipiv_is_soft_disabled())
 		WRITE_ONCE(kvm_svm->avic_physical_id_table[vcpu->vcpu_id], entry);
 
 	/*
-- 
2.54.0