Re: [PATCH v2] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list
2012/7/25 Ben Hutchings b...@decadent.org.uk: On Wed, 2012-07-25 at 20:13 +0800, Wang Sen wrote: When using the commands below to write some data to a virtio-scsi LUN of the QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash. # sudo mkfs.ext4 /dev/sdb (/dev/sdb is the virtio-scsi LUN.) # sudo mount /dev/sdb /mnt # dd if=/dev/zero of=/mnt/file bs=1M count=1024 In current implementation, sg_set_buf is called to add buffers to sg list which is put into the virtqueue eventually. But if there are some HighMem pages in table-sgl you can not get virtual address by sg_virt. So, sg_virt(sg_elem) may return NULL value. This will cause QEMU exit when virtqueue_map_sg is called in QEMU because an invalid GPA is passed by virtqueue. I take Paolo's solution mentioned in last thread to avoid failure on handling flag bits. I have tested the patch on my workstation. QEMU would not crash any more. Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com [...] This is not the correct way to submit a change for stable. See Documentation/stable_kernel_rules.txt. OK, thanks. Ben. -- Ben Hutchings If more than one person is responsible for a bug, no one is at fault. -- -- Wang Sen Addr: XUPT,Xi'an,Shaanxi,China Email: kelvin.x...@gmail.com -- -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH v2] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list
When using the commands below to write some data to a virtio-scsi LUN of the QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash. # sudo mkfs.ext4 /dev/sdb (/dev/sdb is the virtio-scsi LUN.) # sudo mount /dev/sdb /mnt # dd if=/dev/zero of=/mnt/file bs=1M count=1024 In current implementation, sg_set_buf is called to add buffers to sg list which is put into the virtqueue eventually. But if there are some HighMem pages in table-sgl you can not get virtual address by sg_virt. So, sg_virt(sg_elem) may return NULL value. This will cause QEMU exit when virtqueue_map_sg is called in QEMU because an invalid GPA is passed by virtqueue. I take Paolo's solution mentioned in last thread to avoid failure on handling flag bits. I have tested the patch on my workstation. QEMU would not crash any more. Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com --- drivers/scsi/virtio_scsi.c |2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 1b38431..6661610 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -198,7 +198,7 @@ static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx, int i; for_each_sg(table-sgl, sg_elem, table-nents, i) - sg_set_buf(sg[idx++], sg_virt(sg_elem), sg_elem-length); + sg[idx++] = *sg_elem; *p_idx = idx; } -- 1.7.9.5 -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list
On Wed, 2012-07-25 at 20:13 +0800, Wang Sen wrote: When using the commands below to write some data to a virtio-scsi LUN of the QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash. # sudo mkfs.ext4 /dev/sdb (/dev/sdb is the virtio-scsi LUN.) # sudo mount /dev/sdb /mnt # dd if=/dev/zero of=/mnt/file bs=1M count=1024 In current implementation, sg_set_buf is called to add buffers to sg list which is put into the virtqueue eventually. But if there are some HighMem pages in table-sgl you can not get virtual address by sg_virt. So, sg_virt(sg_elem) may return NULL value. This will cause QEMU exit when virtqueue_map_sg is called in QEMU because an invalid GPA is passed by virtqueue. I take Paolo's solution mentioned in last thread to avoid failure on handling flag bits. I have tested the patch on my workstation. QEMU would not crash any more. Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com [...] This is not the correct way to submit a change for stable. See Documentation/stable_kernel_rules.txt. Ben. -- Ben Hutchings If more than one person is responsible for a bug, no one is at fault. signature.asc Description: This is a digitally signed message part
Re: [PATCH v2] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list
On 07/25/2012 03:34 PM, Paolo Bonzini wrote: Il 25/07/2012 14:13, Wang Sen ha scritto: When using the commands below to write some data to a virtio-scsi LUN of the QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash. # sudo mkfs.ext4 /dev/sdb (/dev/sdb is the virtio-scsi LUN.) # sudo mount /dev/sdb /mnt # dd if=/dev/zero of=/mnt/file bs=1M count=1024 In current implementation, sg_set_buf is called to add buffers to sg list which is put into the virtqueue eventually. But if there are some HighMem pages in table-sgl you can not get virtual address by sg_virt. So, sg_virt(sg_elem) may return NULL value. This will cause QEMU exit when virtqueue_map_sg is called in QEMU because an invalid GPA is passed by virtqueue. I take Paolo's solution mentioned in last thread to avoid failure on handling flag bits. Please include an URL or (better) summarize the reason why sg_set_page is not correct in the commit message. For example, replace this paragraph with the following: To fix this, we can simply copy the original scatterlist entries into virtio-scsi's; we need to copy the entries entirely, including the flag bits, so using sg_set_page is not correct. Please send v3 with this change and I'll add my Acked-by. NACK-by: Boaz Harrosh Apart from the HighMem pages problem, where in previous sg_set_buf() code was the marker copied? It was not because it is not needed because the allocation of sg took care of that. For example in 64bit the is no bugs, right? If there was a destination sg_list termination bug, it should be fixed as a separate patch from this HighMem pages problem. But I bet if you inspect the code carefully there isn't such a bug. Cheers Boaz Paolo I have tested the patch on my workstation. QEMU would not crash any more. Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com --- drivers/scsi/virtio_scsi.c |2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 1b38431..6661610 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -198,7 +198,7 @@ static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx, int i; for_each_sg(table-sgl, sg_elem, table-nents, i) -sg_set_buf(sg[idx++], sg_virt(sg_elem), sg_elem-length); +sg[idx++] = *sg_elem; *p_idx = idx; } -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
