Re: [PATCH kvmtool 03/16] virtio/scsi: Allow the use of multiple banks

[Andre Przywara <andre.przywara@arm.com>]

On Mon, 23 Sep 2019 14:35:09 +0100
Alexandru Elisei <alexandru.elisei@arm.com> wrote:

Hi,

> From: Julien Grall <julien.grall@arm.com>
> 
> At the moment, virtio scsi registers only one bank starting at 0. On some
> architectures (like on x86, for example), this may not be true and the
> guest may have multiple memory regions.
> 
> Register all the memory regions to vhost by browsing kvm->mem_banks. The
> code is based on the virtio_net__vhost_init implementation.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>

Reviewed-by: Andre Przywara <andre.przywara@arm.com>

Cheers,
Andre

> ---
>  virtio/scsi.c | 21 +++++++++++++--------
>  1 file changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/virtio/scsi.c b/virtio/scsi.c
> index a72bb2a9a206..63fc4f4635a2 100644
> --- a/virtio/scsi.c
> +++ b/virtio/scsi.c
> @@ -190,24 +190,29 @@ static struct virtio_ops scsi_dev_virtio_ops = {
>  
>  static void virtio_scsi_vhost_init(struct kvm *kvm, struct scsi_dev *sdev)
>  {
> +	struct kvm_mem_bank *bank;
>  	struct vhost_memory *mem;
>  	u64 features;
> -	int r;
> +	int r, i;
>  
>  	sdev->vhost_fd = open("/dev/vhost-scsi", O_RDWR);
>  	if (sdev->vhost_fd < 0)
>  		die_perror("Failed openning vhost-scsi device");
>  
> -	mem = calloc(1, sizeof(*mem) + sizeof(struct vhost_memory_region));
> +	mem = calloc(1, sizeof(*mem) + kvm->mem_slots * sizeof(struct vhost_memory_region));
>  	if (mem == NULL)
>  		die("Failed allocating memory for vhost memory map");
>  
> -	mem->nregions = 1;
> -	mem->regions[0] = (struct vhost_memory_region) {
> -		.guest_phys_addr	= 0,
> -		.memory_size		= kvm->ram_size,
> -		.userspace_addr		= (unsigned long)kvm->ram_start,
> -	};
> +	i = 0;
> +	list_for_each_entry(bank, &kvm->mem_banks, list) {
> +		mem->regions[i] = (struct vhost_memory_region) {
> +			.guest_phys_addr	= bank->guest_phys_addr,
> +			.memory_size		= bank->size,
> +			.userspace_addr		= (unsigned long)bank->host_addr,
> +		};
> +		i++;
> +	}
> +	mem->nregions = i;
>  
>  	r = ioctl(sdev->vhost_fd, VHOST_SET_OWNER);
>  	if (r != 0)