On Thu, 2020-03-05 at 12:44 +0000, pdurr...@amzn.com wrote:
> From: Paul Durrant <pdurr...@amazon.com>
>
> ... and save the MFN.
>
> This patch modifies the 'shared_info' field of struct domain to be
> a structure comprising an MFN and a virtual address. Allocations are
> still done from xenheap, so the virtual address still equates to
> virt_to_mfn() called on the MFN but subsequent patch will change
> this.
> Hence the need to save the MFN.
>
> NOTE: Whist defining the new helpers, virt_to_mfn() in
> common/domain.c
> is made type safe.
> The definition of nmi_reason() in asm-x86/shared.h is also re-
> flowed to avoid overly long lines.
>
> Signed-off-by: Paul Durrant <pdurr...@amazon.com>
> Reviewed-by: Julien Grall <jul...@xen.org>
> ...
>
> +int alloc_shared_info(struct domain *d, unsigned int memflags)
> +{
> + if ( (d->shared_info.virt = alloc_xenheap_pages(0, memflags)) ==
> NULL )
> + return -ENOMEM;
> +
> + d->shared_info.mfn = virt_to_mfn(d->shared_info.virt);
> +
> + clear_page(d->shared_info.virt);
> + share_xen_page_with_guest(mfn_to_page(d->shared_info.mfn), d,
> SHARE_rw);
> +
> + return 0;
> +}
> +
> +void free_shared_info(struct domain *d)
> +{
> + if ( !d->shared_info.virt )
> + return;
> +
> + free_xenheap_page(d->shared_info.virt);
> + d->shared_info.virt = NULL;
> +}
> +
I was going to say that free_xenheap_page() can deal with NULL so we do
not have to return on NULL. But then I found that the final patch needs
to unmap it which cannot deal with NULL anyway, so I no longer have a
strong opinion to do clean-ups here.
Other than that,
Reviewed-by: Hongyan Xia <hongy...@amazon.org>
Hongyan
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