From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
x86@kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
"Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>,
Roman Kagan <rkagan@virtuozzo.com>,
"Denis V . Lunev" <den@openvz.org>
Subject: Re: [PATCH v2 2/3] x86/kvm/hyper-v: remove stale entries from vec_bitmap/auto_eoi_bitmap on vector change
Date: Thu, 8 Mar 2018 22:08:04 +0100 [thread overview]
Message-ID: <20180308210804.GN12290@flask> (raw)
In-Reply-To: <20180301141514.3482-3-vkuznets@redhat.com>
2018-03-01 15:15+0100, Vitaly Kuznetsov:
> 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);
This looks like it solves the problem when we get two SINTs with the
same vector back-to-back , but shouldn't these bits really be cleared on
EOI (either auto or manual)?
Thanks.
next prev parent reply other threads:[~2018-03-08 21:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-01 14:15 [PATCH v2 0/4] x86/kvm/hyper-v: More fixes for TSC page clocksource for Hyper-V on KVM Vitaly Kuznetsov
2018-03-01 14:15 ` [PATCH v2 1/3] x86/kvm/hyper-v: add reenlightenment MSRs support Vitaly Kuznetsov
2018-03-01 14:15 ` [PATCH v2 2/3] x86/kvm/hyper-v: remove stale entries from vec_bitmap/auto_eoi_bitmap on vector change Vitaly Kuznetsov
2018-03-08 21:08 ` Radim Krčmář [this message]
2018-03-09 15:21 ` Vitaly Kuznetsov
2018-03-09 15:45 ` Radim Krčmář
2018-03-01 14:15 ` [PATCH v2 3/3] x86/kvm/hyper-v: inject #GP only when invalid SINTx vector is unmasked Vitaly Kuznetsov
2018-03-01 14:59 ` Roman Kagan
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