Re: [RFCv2 05/16] x86/kvm: Make VirtIO use DMA API in KVM guest

2020-10-21 Thread Halil Pasic
On Tue, 20 Oct 2020 09:18:48 +0300 "Kirill A. Shutemov" wrote: > VirtIO for KVM is a primary way to provide IO. All memory that used for > communication with the host has to be marked as shared. > > The easiest way to archive that is to use DMA API that already knows how > to deal with shared

Re: [RFCv2 05/16] x86/kvm: Make VirtIO use DMA API in KVM guest

2020-10-20 Thread Kirill A. Shutemov
On Tue, Oct 20, 2020 at 09:06:58AM +0100, Christoph Hellwig wrote: > NAK. Any virtio implementation that needs special DMA OPS treatment > needs to set the VIRTIO_F_ACCESS_PLATFORM bit. The only reason the > Xen hack existst is because it slipped in a long time ago and we can't > fix that any

Re: [RFCv2 05/16] x86/kvm: Make VirtIO use DMA API in KVM guest

2020-10-20 Thread Christoph Hellwig
NAK. Any virtio implementation that needs special DMA OPS treatment needs to set the VIRTIO_F_ACCESS_PLATFORM bit. The only reason the Xen hack existst is because it slipped in a long time ago and we can't fix that any more.

[RFCv2 05/16] x86/kvm: Make VirtIO use DMA API in KVM guest

2020-10-20 Thread Kirill A. Shutemov
VirtIO for KVM is a primary way to provide IO. All memory that used for communication with the host has to be marked as shared. The easiest way to archive that is to use DMA API that already knows how to deal with shared memory. Signed-off-by: Kirill A. Shutemov ---