From 309bba39c945ac8ab8083ac05cd6cfe5822968e0 Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Fri, 24 Jun 2022 09:56:56 +0200 Subject: vringh: iterate on iotlb_translate to handle large translations iotlb_translate() can return -ENOBUFS if the bio_vec is not big enough to contain all the ranges for translation. This can happen for example if the VMM maps a large bounce buffer, without using hugepages, that requires more than 16 ranges to translate the addresses. To handle this case, let's extend iotlb_translate() to also return the number of bytes successfully translated. In copy_from_iotlb()/copy_to_iotlb() loops by calling iotlb_translate() several times until we complete the translation. Signed-off-by: Stefano Garzarella Message-Id: <20220624075656.13997-1-sgarzare@redhat.com> Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vringh.c | 78 ++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 56 insertions(+), 22 deletions(-) (limited to 'drivers/vhost/vringh.c') diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index eab55accf381..11f59dd06a74 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -1095,7 +1095,8 @@ EXPORT_SYMBOL(vringh_need_notify_kern); #if IS_REACHABLE(CONFIG_VHOST_IOTLB) static int iotlb_translate(const struct vringh *vrh, - u64 addr, u64 len, struct bio_vec iov[], + u64 addr, u64 len, u64 *translated, + struct bio_vec iov[], int iov_size, u32 perm) { struct vhost_iotlb_map *map; @@ -1136,43 +1137,76 @@ static int iotlb_translate(const struct vringh *vrh, spin_unlock(vrh->iotlb_lock); + if (translated) + *translated = min(len, s); + return ret; } static inline int copy_from_iotlb(const struct vringh *vrh, void *dst, void *src, size_t len) { - struct iov_iter iter; - struct bio_vec iov[16]; - int ret; + u64 total_translated = 0; - ret = iotlb_translate(vrh, (u64)(uintptr_t)src, - len, iov, 16, VHOST_MAP_RO); - if (ret < 0) - return ret; + while (total_translated < len) { + struct bio_vec iov[16]; + struct iov_iter iter; + u64 translated; + int ret; - iov_iter_bvec(&iter, READ, iov, ret, len); + ret = iotlb_translate(vrh, (u64)(uintptr_t)src, + len - total_translated, &translated, + iov, ARRAY_SIZE(iov), VHOST_MAP_RO); + if (ret == -ENOBUFS) + ret = ARRAY_SIZE(iov); + else if (ret < 0) + return ret; - ret = copy_from_iter(dst, len, &iter); + iov_iter_bvec(&iter, READ, iov, ret, translated); - return ret; + ret = copy_from_iter(dst, translated, &iter); + if (ret < 0) + return ret; + + src += translated; + dst += translated; + total_translated += translated; + } + + return total_translated; } static inline int copy_to_iotlb(const struct vringh *vrh, void *dst, void *src, size_t len) { - struct iov_iter iter; - struct bio_vec iov[16]; - int ret; + u64 total_translated = 0; - ret = iotlb_translate(vrh, (u64)(uintptr_t)dst, - len, iov, 16, VHOST_MAP_WO); - if (ret < 0) - return ret; + while (total_translated < len) { + struct bio_vec iov[16]; + struct iov_iter iter; + u64 translated; + int ret; + + ret = iotlb_translate(vrh, (u64)(uintptr_t)dst, + len - total_translated, &translated, + iov, ARRAY_SIZE(iov), VHOST_MAP_WO); + if (ret == -ENOBUFS) + ret = ARRAY_SIZE(iov); + else if (ret < 0) + return ret; - iov_iter_bvec(&iter, WRITE, iov, ret, len); + iov_iter_bvec(&iter, WRITE, iov, ret, translated); + + ret = copy_to_iter(src, translated, &iter); + if (ret < 0) + return ret; + + src += translated; + dst += translated; + total_translated += translated; + } - return copy_to_iter(src, len, &iter); + return total_translated; } static inline int getu16_iotlb(const struct vringh *vrh, @@ -1183,7 +1217,7 @@ static inline int getu16_iotlb(const struct vringh *vrh, int ret; /* Atomic read is needed for getu16 */ - ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), + ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL, &iov, 1, VHOST_MAP_RO); if (ret < 0) return ret; @@ -1204,7 +1238,7 @@ static inline int putu16_iotlb(const struct vringh *vrh, int ret; /* Atomic write is needed for putu16 */ - ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), + ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL, &iov, 1, VHOST_MAP_WO); if (ret < 0) return ret; -- cgit v1.2.3