On 9/25/20 6:02 PM, Pierre Morel wrote:
> When communicating with the host we need to share part of
> the memory.
>
> Let's implement the ultravisor calls for this.
>
> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> Suggested-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> lib/s390x/asm/uv.h | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/lib/s390x/asm/uv.h b/lib/s390x/asm/uv.h
> index 4c2fc48..19019e4 100644
> --- a/lib/s390x/asm/uv.h
> +++ b/lib/s390x/asm/uv.h
> @@ -71,4 +71,37 @@ static inline int uv_call(unsigned long r1, unsigned long r2)
> return cc;
> }
>
> +static inline int share(unsigned long addr, u16 cmd)
> +{
> + struct uv_cb_share uvcb = {
> + .header.cmd = cmd,
> + .header.len = sizeof(uvcb),
> + .paddr = addr
> + };
> +
> + uv_call(0, (u64)&uvcb);
> + return uvcb.header.rc;
That's not a great idea, rc is > 1 for error codes...
In the kernel we check for the cc instead since uv_call() has only 0/1
as possible cc return values.
> +}
> +
> +/*
> + * Guest 2 request to the Ultravisor to make a page shared with the
> + * hypervisor for IO.
> + *
> + * @addr: Real or absolute address of the page to be shared
> + */
> +static inline int uv_set_shared(unsigned long addr)
> +{
> + return share(addr, UVC_CMD_SET_SHARED_ACCESS);
> +}
> +
> +/*
> + * Guest 2 request to the Ultravisor to make a page unshared.
> + *
> + * @addr: Real or absolute address of the page to be unshared
> + */
> +static inline int uv_remove_shared(unsigned long addr)
> +{
> + return share(addr, UVC_CMD_REMOVE_SHARED_ACCESS);
> +}
> +
> #endif
>
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