Re: [Qemu-devel] question about block size and virtual disks

2017-04-25 Thread Kevin Wolf
Am 21.04.2017 um 18:26 hat Chris Friesen geschrieben: > On 04/20/2017 03:21 PM, Eric Blake wrote: > >On 04/20/2017 04:03 PM, Chris Friesen wrote: > > >>Also, does the 4KB block size get "passed-through" to the guest somehow > >>so that the guest knows it needs to use 4KB blocks, or does that need

Re: [Qemu-devel] question about block size and virtual disks

2017-04-21 Thread Chris Friesen
On 04/20/2017 03:21 PM, Eric Blake wrote: On 04/20/2017 04:03 PM, Chris Friesen wrote: Also, does the 4KB block size get "passed-through" to the guest somehow so that the guest knows it needs to use 4KB blocks, or does that need to be explicitly specified via virtio-blk-pci.logical_block_size

Re: [Qemu-devel] question about block size and virtual disks

2017-04-20 Thread Eric Blake
On 04/20/2017 04:03 PM, Chris Friesen wrote: > Hi, > > Suppose the host has a physical disk that only supports 4KB access, with > no 512B fallback. > > If we boot a guest with "cache=none", does the guest need to be able to > handle disks with 4KB blocks or is qemu able to handle guests trying

[Qemu-devel] question about block size and virtual disks

2017-04-20 Thread Chris Friesen
Hi, Suppose the host has a physical disk that only supports 4KB access, with no 512B fallback. If we boot a guest with "cache=none", does the guest need to be able to handle disks with 4KB blocks or is qemu able to handle guests trying to access the disk with 512B granularity? Also, does