From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Thu, 1 Mar 2018 15:15:13 +0100
Patch-mainline: v4.17-rc1
Subject: x86/kvm/hyper-v: remove stale entries from vec_bitmap/auto_eoi_bitmap on vector change
Git-commit: 98f65ad458441ea3a243395345811132ee850093
References: bsc#1107207
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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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>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Acked-by: Olaf Hering <ohering@suse.de>
---
 arch/x86/include/uapi/asm/hyperv.h |  2 ++
 arch/x86/kvm/hyperv.c              | 32 ++++++++++++++++++++++----------
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
--- a/arch/x86/include/uapi/asm/hyperv.h
+++ b/arch/x86/include/uapi/asm/hyperv.h
@@ -320,6 +320,8 @@ 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
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -75,13 +75,30 @@ 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
@@ -89,18 +106,13 @@ 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));