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[83.51.215.31]) by smtp.gmail.com with ESMTPSA id by20sm10484219ejc.74.2021.05.18.11.39.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 May 2021 11:39:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621363149; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YTy8laNpOEvZ5nwMb6BJ8len0GRaZyxbwD2wWuJLiMU=; b=GcGKSasvaJwOzHQI5W/3WaZvbpr3LSLEcKhxKhx+5XkeqzKm4/AAT4fwiG/886TCJQtpx9 yuw9kumwHXUSAcQ+YZzfw7r4rmsKk1oGlu+/WZEIBAbXvurc7lqQ2CJmYAKWXQ3TDjg1M1 DS7ITT3W+Da3Qy7cBQXAXkNmK3y6INg= X-MC-Unique: LnBnTGU8PgOnA1SAF2hsew-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=YTy8laNpOEvZ5nwMb6BJ8len0GRaZyxbwD2wWuJLiMU=; b=tjeHXvpxLYXDRtAL0fGcnQll/iyLi5tsEtz8+RbyygWHKXVt7TXaIxcb/Zj0jPz9gh 4FKnM2JmoYSh+sg8Yh4sLsXzZ8tTbBG4LQLk244WmlnmvbWaMzSObzAPnek3iGWh/20/ WZWf0lORub8JsC1N6ku8H/hC91QWRUzSukUK2eItKDq99Bvt4w2QZQGT0bWMvcvmOLrx mnyzpgtRQDnkawHkG95PDZIxk60e4AvnBTqVVHQFQc+yFJAvZ4/Cc209y8eQVPoNV9X0 ReBCUCWBpEq0yyeLdLDmQtC0KMtcIcH4vf+abRDIRHXOMA2tACk2bnxS5Gw862/bs38w WIBw== X-Gm-Message-State: AOAM531Ztite9UbGhbJalwAXAoJq1vrF4S4EVm5It7e5GkxAKHa2yole WhMGBdH2L559v1wiCQONAgWonmQ9Ymgwlt02kSeMxhqTO8KYyw1BxSNo+qkDkaXK9pBDHZ2lSER xzRWGYndWBAeCfw== X-Received: by 2002:aa7:de1a:: with SMTP id h26mr8579031edv.240.1621363143421; Tue, 18 May 2021 11:39:03 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzewI5q9w4LIUHMUMfEoaVDnvZb3rhKtib+QlWRVX3MXnOn4+YpREw+F3uNlY8D0WfXStwvRg== X-Received: by 2002:aa7:de1a:: with SMTP id h26mr8579019edv.240.1621363143290; Tue, 18 May 2021 11:39:03 -0700 (PDT) From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Cc: Bibo Mao , "Michael S. Tsirkin" , Richard Henderson , Paolo Bonzini , Jiaxun Yang , Peter Xu , Huacai Chen , Peter Maydell , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Stefan Hajnoczi Subject: [RFC PATCH 25/25] hw/virtio: Optimize accesses on vring aligned pointers Date: Tue, 18 May 2021 20:36:55 +0200 Message-Id: <20210518183655.1711377-26-philmd@redhat.com> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20210518183655.1711377-1-philmd@redhat.com> References: <20210518183655.1711377-1-philmd@redhat.com> MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=philmd@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @redhat.com) By the virtio spec [*] the vring is aligned, so the 'idx' and 'flag' fields are also 16-bit aligned. Therefore we can use the load/store *aligned* API to set the value. [*] https://docs.oasis-open.org/virtio/virtio/v1.1/csprd01/virtio-v1.1-cspr= d01.html#x1-430008 Reported-by: Bibo Mao Inspired-by: Stefan Hajnoczi Signed-off-by: Philippe Mathieu-Daud=C3=A9 --- hw/virtio/virtio.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index e02544b2df7..ebee9c4e643 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -296,7 +296,7 @@ static inline uint16_t vring_avail_flags(VirtQueue *vq) return 0; } =20 - return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa); + return virtio_lduw_phys_cached_aligned(vq->vdev, &caches->avail, pa); } =20 /* Called within rcu_read_lock(). */ @@ -309,7 +309,8 @@ static inline uint16_t vring_avail_idx(VirtQueue *vq) return 0; } =20 - vq->shadow_avail_idx =3D virtio_lduw_phys_cached(vq->vdev, &caches->av= ail, pa); + vq->shadow_avail_idx =3D virtio_lduw_phys_cached_aligned(vq->vdev, + &caches->avail,= pa); return vq->shadow_avail_idx; } =20 @@ -359,7 +360,7 @@ static uint16_t vring_used_idx(VirtQueue *vq) return 0; } =20 - return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa); + return virtio_lduw_phys_cached_aligned(vq->vdev, &caches->used, pa); } =20 /* Called within rcu_read_lock(). */ @@ -369,7 +370,7 @@ static inline void vring_used_idx_set(VirtQueue *vq, ui= nt16_t val) hwaddr pa =3D offsetof(VRingUsed, idx); =20 if (caches) { - virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val); + virtio_stw_phys_cached_aligned(vq->vdev, &caches->used, pa, val); address_space_cache_invalidate(&caches->used, pa, sizeof(val)); } =20 @@ -388,8 +389,8 @@ static inline void vring_used_flags_set_bit(VirtQueue *= vq, int mask) return; } =20 - flags =3D virtio_lduw_phys_cached(vq->vdev, &caches->used, pa); - virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask); + flags =3D virtio_lduw_phys_cached_aligned(vq->vdev, &caches->used, pa); + virtio_stw_phys_cached_aligned(vdev, &caches->used, pa, flags | mask); address_space_cache_invalidate(&caches->used, pa, sizeof(flags)); } =20 --=20 2.26.3