linux-kernel - [PART2 RFC v1 9/9] svm: Update AMD IOMMU IRTE with vcpu scheduling information when enable AVIC

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Date:	Fri, 8 Apr 2016 07:49:30 -0500
From:	Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
To:	<pbonzini@...hat.com>, <rkrcmar@...hat.com>, <joro@...tes.org>,
	<bp@...en8.de>, <gleb@...nel.org>, <alex.williamson@...hat.com>
CC:	<kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<wei@...hat.com>, <sherry.hurwitz@....com>,
	Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Subject: [PART2 RFC v1 9/9] svm: Update AMD IOMMU IRTE with vcpu scheduling information when enable AVIC

From: Suravee Suthikulpanit <suravee.suthikulpanit@....com>

In case AVIC is enabled, during vcpu_load/unload, SVM needs to update
IOMMU IRTE with appropriate host physical APIC ID. Also, when
vcpu_blocking/unblocking, SVM needs to update the is-running bit in
the IOMMU IRTE. Both are achieved via calling amd_iommu_update_ga().

However, if GA mode is not enabled for the pass-through device,
IOMMU driver will simply just return when calling amd_iommu_update_ga.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
---
 arch/x86/kvm/svm.c | 50 +++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 43 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 38fd7a3..3b9a0b2 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1397,11 +1397,24 @@ free_avic:
 	return err;
 }
 
+static inline int
+avic_update_iommu(struct kvm_vcpu *vcpu, int cpu, phys_addr_t pa, bool r)
+{
+	struct kvm_arch *vm_data = &vcpu->kvm->arch;
+
+	if (!kvm_arch_has_assigned_device(vcpu->kvm))
+		return 0;
+
+	return amd_iommu_update_ga(vcpu->vcpu_id, cpu, vm_data->avic_tag,
+				   (pa & AVIC_HPA_MASK), r);
+}
+
 /**
  * This function is called during VCPU halt/unhalt.
  */
 static int avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
 {
+	int ret = 0;
 	u64 entry;
 	int h_physical_id = __default_cpu_present_to_apicid(vcpu->cpu);
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -1420,17 +1433,27 @@ static int avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
 		WARN_ON((entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK) == 0);
 
 	entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
-	if (is_run)
+	if (is_run) {
 		entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
-	WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+		WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
 
-	return 0;
+		ret = avic_update_iommu(vcpu, h_physical_id,
+					page_to_phys(svm->avic_backing_page), 1);
+	} else {
+		ret = avic_update_iommu(vcpu, h_physical_id,
+					page_to_phys(svm->avic_backing_page), 0);
+
+		WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+	}
+
+	return ret;
 }
 
 static int avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu, bool is_load)
 {
-	u64 entry;
+	int ret = 0;
 	int h_physical_id = __default_cpu_present_to_apicid(cpu);
+	u64 entry;
 	struct vcpu_svm *svm = to_svm(vcpu);
 
 	if (!svm_vcpu_avic_enabled(svm))
@@ -1443,16 +1466,29 @@ static int avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu, bool is_load)
 	entry = READ_ONCE(*(svm->avic_physical_id_cache));
 	WARN_ON(is_load && (entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK));
 
-	entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
 	if (is_load) {
 		entry &= ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK;
 		entry |= (h_physical_id & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK);
+
+		entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
 		if (!svm->avic_is_blocking)
 			entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+		WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+
+		ret = avic_update_iommu(vcpu, h_physical_id,
+					page_to_phys(svm->avic_backing_page),
+					!svm->avic_is_blocking);
+	} else {
+		if (entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK) {
+			ret = avic_update_iommu(vcpu, h_physical_id,
+						page_to_phys(svm->avic_backing_page), 0);
+
+			entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+			WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+		}
 	}
-	WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
 
-	return 0;
+	return ret;
 }
 
 static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
-- 
1.9.1