diff mbox

[2/3] x86/kvm/hyper-v: remove stale entries from vec_bitmap/auto_eoi_bitmap on vector change

Message ID 20180228134401.6544-3-vkuznets@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Vitaly Kuznetsov Feb. 28, 2018, 1:44 p.m. UTC 
When a new vector is written to SINx we update vec_bitmap/auto_eoi_bitmap
but we forget to remove old vector from these masks (in case it is not
present in some other SINTx).

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 arch/x86/include/uapi/asm/hyperv.h |  2 ++
 arch/x86/kvm/hyperv.c              | 32 ++++++++++++++++++++++----------
 2 files changed, 24 insertions(+), 10 deletions(-)

Comments

Roman Kagan Feb. 28, 2018, 2:38 p.m. UTC | #1 
On Wed, Feb 28, 2018 at 02:44:00PM +0100, Vitaly Kuznetsov wrote:
> When a new vector is written to SINx we update vec_bitmap/auto_eoi_bitmap
> but we forget to remove old vector from these masks (in case it is not
> present in some other SINTx).
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
>  arch/x86/include/uapi/asm/hyperv.h |  2 ++
>  arch/x86/kvm/hyperv.c              | 32 ++++++++++++++++++++++----------
>  2 files changed, 24 insertions(+), 10 deletions(-)

Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
diff mbox

Patch

diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
index 197c2e6c7376..62c778a303a1 100644
--- a/arch/x86/include/uapi/asm/hyperv.h
+++ b/arch/x86/include/uapi/asm/hyperv.h
@@ -318,6 +318,8 @@  typedef struct _HV_REFERENCE_TSC_PAGE {
 #define HV_SYNIC_SINT_COUNT		(16)
 /* Define the expected SynIC version. */
 #define HV_SYNIC_VERSION_1		(0x1)
+/* Valid SynIC vectors are 16-255. */
+#define HV_SYNIC_FIRST_VALID_VECTOR	(16)
 
 #define HV_SYNIC_CONTROL_ENABLE		(1ULL << 0)
 #define HV_SYNIC_SIMP_ENABLE		(1ULL << 0)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 05f414525538..6d14f808145d 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -74,13 +74,30 @@  static bool synic_has_vector_auto_eoi(struct kvm_vcpu_hv_synic *synic,
 	return false;
 }
 
+static void synic_update_vector(struct kvm_vcpu_hv_synic *synic,
+				int vector)
+{
+	if (vector < HV_SYNIC_FIRST_VALID_VECTOR)
+		return;
+
+	if (synic_has_vector_connected(synic, vector))
+		__set_bit(vector, synic->vec_bitmap);
+	else
+		__clear_bit(vector, synic->vec_bitmap);
+
+	if (synic_has_vector_auto_eoi(synic, vector))
+		__set_bit(vector, synic->auto_eoi_bitmap);
+	else
+		__clear_bit(vector, synic->auto_eoi_bitmap);
+}
+
 static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint,
 			  u64 data, bool host)
 {
-	int vector;
+	int vector, old_vector;
 
 	vector = data & HV_SYNIC_SINT_VECTOR_MASK;
-	if (vector < 16 && !host)
+	if (vector < HV_SYNIC_FIRST_VALID_VECTOR && !host)
 		return 1;
 	/*
 	 * Guest may configure multiple SINTs to use the same vector, so
@@ -88,18 +105,13 @@  static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint,
 	 * bitmap of vectors with auto-eoi behavior.  The bitmaps are
 	 * updated here, and atomically queried on fast paths.
 	 */
+	old_vector = synic_read_sint(synic, sint) & HV_SYNIC_SINT_VECTOR_MASK;
 
 	atomic64_set(&synic->sint[sint], data);
 
-	if (synic_has_vector_connected(synic, vector))
-		__set_bit(vector, synic->vec_bitmap);
-	else
-		__clear_bit(vector, synic->vec_bitmap);
+	synic_update_vector(synic, old_vector);
 
-	if (synic_has_vector_auto_eoi(synic, vector))
-		__set_bit(vector, synic->auto_eoi_bitmap);
-	else
-		__clear_bit(vector, synic->auto_eoi_bitmap);
+	synic_update_vector(synic, vector);
 
 	/* Load SynIC vectors into EOI exit bitmap */
 	kvm_make_request(KVM_REQ_SCAN_IOAPIC, synic_to_vcpu(synic));