KVM: extend in-kernel mmio to handle >8 byte transactions

Needed for coalesced mmio using sse.

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 46 insertions, 12 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 692c70d6fd02..3b234c18b635 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3596,20 +3596,43 @@ static void kvm_init_msr_list(void)
 static int vcpu_mmio_write(struct kvm_vcpu *vcpu, gpa_t addr, int len,
                            const void *v)
 {
-        if (vcpu->arch.apic &&
-            !kvm_iodevice_write(&vcpu->arch.apic->dev, addr, len, v))
-                return 0;
+        int handled = 0;
+        int n;
+
+        do {
+                n = min(len, 8);
+                if (!(vcpu->arch.apic &&
+                      !kvm_iodevice_write(&vcpu->arch.apic->dev, addr, n, v))
+                    && kvm_io_bus_write(vcpu->kvm, KVM_MMIO_BUS, addr, n, v))
+                        break;
+                handled += n;
+                addr += n;
+                len -= n;
+                v += n;
+        } while (len);
 
-        return kvm_io_bus_write(vcpu->kvm, KVM_MMIO_BUS, addr, len, v);
+        return handled;
 }
 
 static int vcpu_mmio_read(struct kvm_vcpu *vcpu, gpa_t addr, int len, void *v)
 {
-        if (vcpu->arch.apic &&
-            !kvm_iodevice_read(&vcpu->arch.apic->dev, addr, len, v))
-                return 0;
+        int handled = 0;
+        int n;
+
+        do {
+                n = min(len, 8);
+                if (!(vcpu->arch.apic &&
+                      !kvm_iodevice_read(&vcpu->arch.apic->dev, addr, n, v))
+                    && kvm_io_bus_read(vcpu->kvm, KVM_MMIO_BUS, addr, n, v))
+                        break;
+                trace_kvm_mmio(KVM_TRACE_MMIO_READ, n, addr, *(u64 *)v);
+                handled += n;
+                addr += n;
+                len -= n;
+                v += n;
+        } while (len);
 
-        return kvm_io_bus_read(vcpu->kvm, KVM_MMIO_BUS, addr, len, v);
+        return handled;
 }
 
 static void kvm_set_segment(struct kvm_vcpu *vcpu,
@@ -3769,6 +3792,7 @@ static int emulator_read_emulated(unsigned long addr,
                                   struct kvm_vcpu *vcpu)
 {
         gpa_t                 gpa;
+        int handled;
 
         if (vcpu->mmio_read_completed) {
                 memcpy(val, vcpu->mmio_data, bytes);
@@ -3795,10 +3819,14 @@ mmio:
         /*
          * Is this MMIO handled locally?
          */
-        if (!vcpu_mmio_read(vcpu, gpa, bytes, val)) {
-                trace_kvm_mmio(KVM_TRACE_MMIO_READ, bytes, gpa, *(u64 *)val);
+        handled = vcpu_mmio_read(vcpu, gpa, bytes, val);
+
+        if (handled == bytes)
                 return X86EMUL_CONTINUE;
-        }
+
+        gpa += handled;
+        bytes -= handled;
+        val += handled;
 
         trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, bytes, gpa, 0);
 
@@ -3830,6 +3858,7 @@ static int emulator_write_emulated_onepage(unsigned long addr,
                                            struct kvm_vcpu *vcpu)
 {
         gpa_t                 gpa;
+        int handled;
 
         gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, exception);
 
@@ -3848,9 +3877,14 @@ mmio:
         /*
          * Is this MMIO handled locally?
          */
-        if (!vcpu_mmio_write(vcpu, gpa, bytes, val))
+        handled = vcpu_mmio_write(vcpu, gpa, bytes, val);
+        if (handled == bytes)
                 return X86EMUL_CONTINUE;
 
+        gpa += handled;
+        bytes -= handled;
+        val += handled;
+
         vcpu->mmio_needed = 1;
         vcpu->run->exit_reason = KVM_EXIT_MMIO;
         vcpu->run->mmio.phys_addr = vcpu->mmio_phys_addr = gpa;