[PATCH v2 2/3] x86/kvm/hyper-v: remove stale entries from vec_bitmap/auto_eoi_bitmap on vector change

Vitaly Kuznetsov
2018-03-01T14:15:28Z

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>
---
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
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));
--
2.14.3