[PATCH v2 2/3] kvm/x86: Convert iommu_flags to iommu_noncoherent

Alex Williamson
2013-10-30T17:02:30Z

Default to operating in coherent mode. This simplifies the logic when
we switch to a model of registering and unregistering noncoherent I/O
with KVM.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
arch/ia64/include/asm/kvm_host.h | 2 +-
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/vmx.c | 2 +-
arch/x86/kvm/x86.c | 2 +-
include/linux/kvm_host.h | 3 ---
virt/kvm/iommu.c | 16 ++++++++--------
6 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/arch/ia64/include/asm/kvm_host.h b/arch/ia64/include/asm/kvm_host.h
index 989dd3f..1933b7a 100644
--- a/arch/ia64/include/asm/kvm_host.h
+++ b/arch/ia64/include/asm/kvm_host.h
@@ -480,7 +480,7 @@ struct kvm_arch {

struct list_head assigned_dev_head;
struct iommu_domain *iommu_domain;
- int iommu_flags;
+ bool iommu_noncoherent;

unsigned long irq_sources_bitmap;
unsigned long irq_states[KVM_IOAPIC_NUM_PINS];
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c76ff74..1b6b5f9 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -557,7 +557,7 @@ struct kvm_arch {

struct list_head assigned_dev_head;
struct iommu_domain *iommu_domain;
- int iommu_flags;
+ bool iommu_noncoherent;
struct kvm_pic *vpic;
struct kvm_ioapic *vioapic;
struct kvm_pit *vpit;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2b2fce1..5d0e3ab 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7411,7 +7411,7 @@ static u64 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
if (is_mmio)
ret = MTRR_TYPE_UNCACHABLE << VMX_EPT_MT_EPTE_SHIFT;
else if (vcpu->kvm->arch.iommu_domain &&
- !(vcpu->kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY))
+ vcpu->kvm->arch.iommu_noncoherent)
ret = kvm_get_guest_memory_type(vcpu, gfn) <<
VMX_EPT_MT_EPTE_SHIFT;
else
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e5ca72a..b1231b0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2716,7 +2716,7 @@ static void wbinvd_ipi(void *garbage)
static bool need_emulate_wbinvd(struct kvm_vcpu *vcpu)
{
return vcpu->kvm->arch.iommu_domain &&
- !(vcpu->kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY);
+ vcpu->kvm->arch.iommu_noncoherent;
}

void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 279002b..46ce3d1 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -747,9 +747,6 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
int kvm_request_irq_source_id(struct kvm *kvm);
void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id);

-/* For vcpu->arch.iommu_flags */
-#define KVM_IOMMU_CACHE_COHERENCY 0x1
-
#ifdef CONFIG_KVM_DEVICE_ASSIGNMENT
int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot);
void kvm_iommu_unmap_pages(struct kvm *kvm, struct kvm_memory_slot *slot);
diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index 72a130b..9cde444 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -79,7 +79,7 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
flags = IOMMU_READ;
if (!(slot->flags & KVM_MEM_READONLY))
flags |= IOMMU_WRITE;
- if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY)
+ if (!kvm->arch.iommu_noncoherent)
flags |= IOMMU_CACHE;

@@ -158,7 +158,8 @@ int kvm_assign_device(struct kvm *kvm,
{
struct pci_dev *pdev = NULL;
struct iommu_domain *domain = kvm->arch.iommu_domain;
- int r, last_flags;
+ int r;
+ bool noncoherent;

/* check if iommu exists and in use */
if (!domain)
@@ -174,15 +175,13 @@ int kvm_assign_device(struct kvm *kvm,
return r;
}

- last_flags = kvm->arch.iommu_flags;
- if (iommu_domain_has_cap(kvm->arch.iommu_domain,
- IOMMU_CAP_CACHE_COHERENCY))
- kvm->arch.iommu_flags |= KVM_IOMMU_CACHE_COHERENCY;
+ noncoherent = !iommu_domain_has_cap(kvm->arch.iommu_domain,
+ IOMMU_CAP_CACHE_COHERENCY);

/* Check if need to update IOMMU page table for guest memory */
- if ((last_flags ^ kvm->arch.iommu_flags) ==
- KVM_IOMMU_CACHE_COHERENCY) {
+ if (noncoherent != kvm->arch.iommu_noncoherent) {
kvm_iommu_unmap_memslots(kvm);
+ kvm->arch.iommu_noncoherent = noncoherent;
r = kvm_iommu_map_memslots(kvm);
if (r)
goto out_unmap;
@@ -350,6 +349,7 @@ int kvm_iommu_unmap_guest(struct kvm *kvm)
mutex_lock(&kvm->slots_lock);
kvm_iommu_unmap_memslots(kvm);
kvm->arch.iommu_domain = NULL;
+ kvm->arch.iommu_noncoherent = false;
mutex_unlock(&kvm->slots_lock);

iommu_domain_free(domain);