diff mbox

[PATCHv5,1/4] Provide userspace IO exit completion callback.

Message ID 1343659101-24877-2-git-send-email-gleb@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Gleb Natapov July 30, 2012, 2:38 p.m. UTC 
Current code assumes that IO exit was due to instruction emulation
and handles execution back to emulator directly. This patch adds new
userspace IO exit completion callback that can be set by any other code
that caused IO exit to userspace.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |    1 +
 arch/x86/kvm/x86.c              |   92 +++++++++++++++++++++++----------------
 2 files changed, 56 insertions(+), 37 deletions(-)

Comments

Marcelo Tosatti Aug. 2, 2012, 7:26 p.m. UTC | #1 
On Mon, Jul 30, 2012 at 05:38:18PM +0300, Gleb Natapov wrote:
>  	int r;
> @@ -5554,9 +5568,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
>  		}
>  	}
>  
> -	r = complete_mmio(vcpu);
> -	if (r <= 0)
> -		goto out;
> +	if (unlikely(vcpu->arch.complete_userspace_io)) {
> +		int (*cui)(struct kvm_vcpu *) = vcpu->arch.complete_userspace_io;
> +		vcpu->arch.complete_userspace_io = NULL;
> +		r = cui(vcpu);
> +		if (r <= 0)
> +			goto out;
> +	}

Would it be worthwhile to add BUG/WARN_ONs here checking for
variables that represent valid mmio/pio, but without
complete_userspace_io function pointer set? (you do that in 
the reverse case, inside the complete_userspace_io 
function pointers).

--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Gleb Natapov Aug. 5, 2012, 2:49 p.m. UTC | #2 
On Thu, Aug 02, 2012 at 04:26:29PM -0300, Marcelo Tosatti wrote:
> On Mon, Jul 30, 2012 at 05:38:18PM +0300, Gleb Natapov wrote:
> >  	int r;
> > @@ -5554,9 +5568,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> >  		}
> >  	}
> >  
> > -	r = complete_mmio(vcpu);
> > -	if (r <= 0)
> > -		goto out;
> > +	if (unlikely(vcpu->arch.complete_userspace_io)) {
> > +		int (*cui)(struct kvm_vcpu *) = vcpu->arch.complete_userspace_io;
> > +		vcpu->arch.complete_userspace_io = NULL;
> > +		r = cui(vcpu);
> > +		if (r <= 0)
> > +			goto out;
> > +	}
> 
> Would it be worthwhile to add BUG/WARN_ONs here checking for
> variables that represent valid mmio/pio, but without
> complete_userspace_io function pointer set? (you do that in 
> the reverse case, inside the complete_userspace_io 
> function pointers).
There are never too much asserts :), But I wouldn't want to resend the
series just for that, so if there are other comments that will require
me to resend the series anyway I'll add asserts too.

--
			Gleb.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 48e7131..37f4f11 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -414,6 +414,7 @@  struct kvm_vcpu_arch {
 	struct x86_emulate_ctxt emulate_ctxt;
 	bool emulate_regs_need_sync_to_vcpu;
 	bool emulate_regs_need_sync_from_vcpu;
+	int (*complete_userspace_io)(struct kvm_vcpu *vcpu);
 
 	gpa_t time;
 	struct pvclock_vcpu_time_info hv_clock;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b6379e5..41c0c3d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4539,6 +4539,9 @@  static bool retry_instruction(struct x86_emulate_ctxt *ctxt,
 	return true;
 }
 
+static int complete_emulated_mmio(struct kvm_vcpu *vcpu);
+static int complete_emulated_pio(struct kvm_vcpu *vcpu);
+
 int x86_emulate_instruction(struct kvm_vcpu *vcpu,
 			    unsigned long cr2,
 			    int emulation_type,
@@ -4609,13 +4612,16 @@  restart:
 	} else if (vcpu->arch.pio.count) {
 		if (!vcpu->arch.pio.in)
 			vcpu->arch.pio.count = 0;
-		else
+		else {
 			writeback = false;
+			vcpu->arch.complete_userspace_io = complete_emulated_pio;
+		}
 		r = EMULATE_DO_MMIO;
 	} else if (vcpu->mmio_needed) {
 		if (!vcpu->mmio_is_write)
 			writeback = false;
 		r = EMULATE_DO_MMIO;
+		vcpu->arch.complete_userspace_io = complete_emulated_mmio;
 	} else if (r == EMULATION_RESTART)
 		goto restart;
 	else
@@ -5471,6 +5477,24 @@  static int __vcpu_run(struct kvm_vcpu *vcpu)
 	return r;
 }
 
+static inline int complete_emulated_io(struct kvm_vcpu *vcpu)
+{
+	int r;
+	vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+	r = emulate_instruction(vcpu, EMULTYPE_NO_DECODE);
+	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+	if (r != EMULATE_DONE)
+		return 0;
+	return 1;
+}
+
+static int complete_emulated_pio(struct kvm_vcpu *vcpu)
+{
+	BUG_ON(!vcpu->arch.pio.count);
+
+	return complete_emulated_io(vcpu);
+}
+
 /*
  * Implements the following, as a state machine:
  *
@@ -5487,47 +5511,37 @@  static int __vcpu_run(struct kvm_vcpu *vcpu)
  *      copy data
  *      exit
  */
-static int complete_mmio(struct kvm_vcpu *vcpu)
+static int complete_emulated_mmio(struct kvm_vcpu *vcpu)
 {
 	struct kvm_run *run = vcpu->run;
 	struct kvm_mmio_fragment *frag;
-	int r;
 
-	if (!(vcpu->arch.pio.count || vcpu->mmio_needed))
-		return 1;
+	BUG_ON(!vcpu->mmio_needed);
 
-	if (vcpu->mmio_needed) {
-		/* Complete previous fragment */
-		frag = &vcpu->mmio_fragments[vcpu->mmio_cur_fragment++];
-		if (!vcpu->mmio_is_write)
-			memcpy(frag->data, run->mmio.data, frag->len);
-		if (vcpu->mmio_cur_fragment == vcpu->mmio_nr_fragments) {
-			vcpu->mmio_needed = 0;
-			if (vcpu->mmio_is_write)
-				return 1;
-			vcpu->mmio_read_completed = 1;
-			goto done;
-		}
-		/* Initiate next fragment */
-		++frag;
-		run->exit_reason = KVM_EXIT_MMIO;
-		run->mmio.phys_addr = frag->gpa;
+	/* Complete previous fragment */
+	frag = &vcpu->mmio_fragments[vcpu->mmio_cur_fragment++];
+	if (!vcpu->mmio_is_write)
+		memcpy(frag->data, run->mmio.data, frag->len);
+	if (vcpu->mmio_cur_fragment == vcpu->mmio_nr_fragments) {
+		vcpu->mmio_needed = 0;
 		if (vcpu->mmio_is_write)
-			memcpy(run->mmio.data, frag->data, frag->len);
-		run->mmio.len = frag->len;
-		run->mmio.is_write = vcpu->mmio_is_write;
-		return 0;
-
-	}
-done:
-	vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
-	r = emulate_instruction(vcpu, EMULTYPE_NO_DECODE);
-	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
-	if (r != EMULATE_DONE)
-		return 0;
-	return 1;
+			return 1;
+		vcpu->mmio_read_completed = 1;
+		return complete_emulated_io(vcpu);
+	}
+	/* Initiate next fragment */
+	++frag;
+	run->exit_reason = KVM_EXIT_MMIO;
+	run->mmio.phys_addr = frag->gpa;
+	if (vcpu->mmio_is_write)
+		memcpy(run->mmio.data, frag->data, frag->len);
+	run->mmio.len = frag->len;
+	run->mmio.is_write = vcpu->mmio_is_write;
+	vcpu->arch.complete_userspace_io = complete_emulated_mmio;
+	return 0;
 }
 
+
 int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
 	int r;
@@ -5554,9 +5568,13 @@  int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 		}
 	}
 
-	r = complete_mmio(vcpu);
-	if (r <= 0)
-		goto out;
+	if (unlikely(vcpu->arch.complete_userspace_io)) {
+		int (*cui)(struct kvm_vcpu *) = vcpu->arch.complete_userspace_io;
+		vcpu->arch.complete_userspace_io = NULL;
+		r = cui(vcpu);
+		if (r <= 0)
+			goto out;
+	}
 
 	r = __vcpu_run(vcpu);