In order to support a userspace IOAPIC interacting with an in kernel
APIC, the EOI exit bitmaps need to be configurable.
If the IOAPIC is in userspace (i.e. the irqchip has been split), the
EOI exit bitmaps will be set whenever the GSI Routes are configured.
In particular, for the low MSI routes are reservable for userspace
IOAPICs. For these MSI routes, the EOI Exit bit corresponding to the
destination vector of the route will be set for the destination VCPU.
The intention is for the userspace IOAPICs to use the reservable MSI
routes to inject interrupts into the guest.
This is a slight abuse of the notion of an MSI Route, given that MSIs
classically bypass the IOAPIC. It might be worthwhile to add an
additional route type to improve clarity.
Compile tested for Intel x86.
Signed-off-by: Steve Rutherford <srutherford@xxxxxxxxxx>
---
Documentation/virtual/kvm/api.txt | 8 ++++----
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/ioapic.h | 2 ++
arch/x86/kvm/irq_comm.c | 42 +++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/lapic.c | 3 +--
arch/x86/kvm/x86.c | 29 +++++++++++++++++----------
include/linux/kvm_host.h | 21 +++++++++++++++++++-
virt/kvm/irqchip.c | 13 ++----------
8 files changed, 91 insertions(+), 28 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index ec0cb19..e5e3e94 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3258,10 +3258,10 @@ Valid values for 'type' are:
As with SHUTDOWN, userspace can choose to ignore the request, or
to schedule the reset to occur in the future and may call KVM_RUN again.
- /* KVM_EXIT_IOAPIC_EOI */
- struct {
- __u8 vector;
- } eoi;
+ /* KVM_EXIT_IOAPIC_EOI */
+ struct {
+ __u8 vector;
+ } eoi;
Indicates that the VCPU's in-kernel local APIC received an EOI for a
level-triggered IOAPIC interrupt. This exit only triggers when the
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2778d36..4f439ff 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -644,6 +644,7 @@ struct kvm_arch {
u64 disabled_quirks;
bool irqchip_split;
+ u8 nr_reserved_ioapic_pins;
};
struct kvm_vm_stat {
diff --git a/arch/x86/kvm/ioapic.h b/arch/x86/kvm/ioapic.h
index d8cc54b..f6ce112 100644
--- a/arch/x86/kvm/ioapic.h
+++ b/arch/x86/kvm/ioapic.h
@@ -9,6 +9,7 @@ struct kvm;
struct kvm_vcpu;
#define IOAPIC_NUM_PINS KVM_IOAPIC_NUM_PINS
+#define MAX_NR_RESERVED_IOAPIC_PINS 48
#define IOAPIC_VERSION_ID 0x11 /* IOAPIC version */
#define IOAPIC_EDGE_TRIG 0
#define IOAPIC_LEVEL_TRIG 1
@@ -132,4 +133,5 @@ int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state);
void kvm_ioapic_scan_entry(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap,
u32 *tmr);
+void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap);
#endif
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 67f6b62..da4827f 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -335,3 +335,45 @@ int kvm_setup_empty_irq_routing(struct kvm *kvm)
{
return kvm_set_irq_routing(kvm, empty_routing, 0, 0);
}
+
+void kvm_arch_irq_routing_update(struct kvm *kvm)
+{
+ if (ioapic_in_kernel(kvm) || !irqchip_in_kernel(kvm))
+ return;
+ kvm_make_scan_ioapic_request(kvm);
+}
+
+void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
+{
+ struct kvm *kvm = vcpu->kvm;
+ struct kvm_kernel_irq_routing_entry *entry;
+ struct kvm_irq_routing_table *table;
+ u32 i, nr_ioapic_pins;
+ int idx;
+
+ /* kvm->irq_routing must be read after clearing
+ * KVM_SCAN_IOAPIC. */
+ smp_mb();
+ idx = srcu_read_lock(&kvm->irq_srcu);
+ table = kvm->irq_routing;
+ nr_ioapic_pins = min_t(u32, table->nr_rt_entries,
+ kvm->arch.nr_reserved_ioapic_pins);
+ for (i = 0; i < nr_ioapic_pins; ++i) {
+ hlist_for_each_entry(entry, &table->map[i], link) {
+ u32 dest_id, dest_mode;
+
+ if (entry->type != KVM_IRQ_ROUTING_MSI)
+ continue;
+ dest_id = (entry->msi.address_lo >> 12) & 0xff;
+ dest_mode = (entry->msi.address_lo >> 2) & 0x1;
+ if (kvm_apic_match_dest(vcpu, NULL, 0, dest_id,
+ dest_mode)) {
+ u32 vector = entry->msi.data & 0xff;
+
+ __set_bit(vector,
+ (unsigned long *) eoi_exit_bitmap);
+ }
+ }
+ }
+ srcu_read_unlock(&kvm->irq_srcu, idx);
+}
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e2ae4b4..45be02b 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -209,8 +209,7 @@ out:
if (old)
kfree_rcu(old, rcu);
- if (!irqchip_split(kvm))
- kvm_vcpu_request_scan_ioapic(kvm);
+ kvm_make_scan_ioapic_request(kvm);
}
static inline void apic_set_spiv(struct kvm_lapic *apic, u32 val)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3b05c01..a1a1c4a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3933,12 +3933,17 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
if (irqchip_in_kernel(kvm))
goto split_irqchip_unlock;
r = -EINVAL;
- if (atomic_read(&kvm->online_vcpus))
- goto split_irqchip_unlock;
- r = kvm_setup_empty_irq_routing(kvm);
- if (r)
+ if (cap->args[0] > MAX_NR_RESERVED_IOAPIC_PINS)
goto split_irqchip_unlock;
- kvm->arch.irqchip_split = true;
+ if (!irqchip_split(kvm)) {
+ if (atomic_read(&kvm->online_vcpus))
+ goto split_irqchip_unlock;
+ r = kvm_setup_empty_irq_routing(kvm);
+ if (r)
+ goto split_irqchip_unlock;
+ kvm->arch.irqchip_split = true;
+ }
+ kvm->arch.nr_reserved_ioapic_pins = cap->args[0];
r = 0;
split_irqchip_unlock:
mutex_unlock(&kvm->lock);
@@ -6280,18 +6285,22 @@ static void process_nmi(struct kvm_vcpu *vcpu)
static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
{
- u64 eoi_exit_bitmap[4];
+ struct kvm *kvm = vcpu->kvm;
u32 tmr[8];
if (!kvm_apic_hw_enabled(vcpu->arch.apic))
return;
- memset(eoi_exit_bitmap, 0, 32);
+ memset(vcpu->arch.eoi_exit_bitmaps, 0, 32);
memset(tmr, 0, 32);
+ if (irqchip_split(kvm))
+ kvm_scan_ioapic_routes(vcpu, vcpu->arch.eoi_exit_bitmaps);
+ else
+ kvm_ioapic_scan_entry(vcpu, vcpu->arch.eoi_exit_bitmaps, tmr);
+ kvm_x86_ops->load_eoi_exitmap(vcpu, vcpu->arch.eoi_exit_bitmaps);
- kvm_ioapic_scan_entry(vcpu, eoi_exit_bitmap, tmr);
- kvm_x86_ops->load_eoi_exitmap(vcpu, eoi_exit_bitmap);
- kvm_apic_update_tmr(vcpu, tmr);
+ if (!irqchip_split(kvm))
+ kvm_apic_update_tmr(vcpu, tmr);
}
static void kvm_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c6df36f..83d8d7a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -323,6 +323,17 @@ struct kvm_kernel_irq_routing_entry {
struct hlist_node link;
};
+struct kvm_irq_routing_table {
+ int chip[KVM_NR_IRQCHIPS][KVM_IRQCHIP_NUM_PINS];
+ struct kvm_kernel_irq_routing_entry *rt_entries;
+ u32 nr_rt_entries;
+ /*
+ * Array indexed by gsi. Each entry contains list of irq chips
+ * the gsi is connected to.
+ */
+ struct hlist_head map[0];
+};
+
#ifndef KVM_PRIVATE_MEM_SLOTS
#define KVM_PRIVATE_MEM_SLOTS 0
#endif
@@ -438,10 +449,19 @@ void vcpu_put(struct kvm_vcpu *vcpu);
#ifdef __KVM_HAVE_IOAPIC
void kvm_vcpu_request_scan_ioapic(struct kvm *kvm);
+void kvm_arch_irq_routing_update(struct kvm *kvm);
+u8 kvm_arch_nr_userspace_ioapic_pins(struct kvm *kvm);
#else
static inline void kvm_vcpu_request_scan_ioapic(struct kvm *kvm)
{
}
+static inline void kvm_arch_irq_routing_update(struct kvm *kvm)
+{
+}
+static inline u8 kvm_arch_nr_userspace_ioapic_pins(struct kvm *kvm)
+{
+ return 0;
+}
#endif
#ifdef CONFIG_HAVE_KVM_IRQFD
@@ -1093,4 +1113,3 @@ static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val)
}
#endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */
#endif
-
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index 1d56a90..8867e1d 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -31,17 +31,6 @@
#include <trace/events/kvm.h>
#include "irq.h"
-struct kvm_irq_routing_table {
- int chip[KVM_NR_IRQCHIPS][KVM_IRQCHIP_NUM_PINS];
- struct kvm_kernel_irq_routing_entry *rt_entries;
- u32 nr_rt_entries;
- /*
- * Array indexed by gsi. Each entry contains list of irq chips
- * the gsi is connected to.
- */
- struct hlist_head map[0];
-};
-
int kvm_irq_map_gsi(struct kvm *kvm,
struct kvm_kernel_irq_routing_entry *entries, int gsi)
{
@@ -203,6 +192,8 @@ int kvm_set_irq_routing(struct kvm *kvm,
kvm_irq_routing_update(kvm);
mutex_unlock(&kvm->irq_lock);
+ kvm_arch_irq_routing_update(kvm);
+
synchronize_srcu_expedited(&kvm->irq_srcu);
new = old;
--
2.2.0.rc0.207.ga3a616c
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