On 28.05.2021 19:39, Roger Pau Monne wrote:
> --- a/xen/arch/x86/mm/p2m-ept.c
> +++ b/xen/arch/x86/mm/p2m-ept.c
> @@ -487,11 +487,12 @@ static int ept_invalidate_emt_range(struct p2m_domain
> *p2m,
> }
>
> int epte_get_entry_emt(struct domain *d, gfn_t gfn, mfn_t mfn,
> - unsigned int order, bool *ipat, bool direct_mmio)
> + unsigned int order, bool *ipat, p2m_type_t type)
> {
> int gmtrr_mtype, hmtrr_mtype;
> struct vcpu *v = current;
> unsigned long i;
> + bool direct_mmio = type == p2m_mmio_direct;
I don't think this variable is worthwhile to retain/introduce:
> @@ -535,9 +536,33 @@ int epte_get_entry_emt(struct domain *d, gfn_t gfn,
> mfn_t mfn,
> }
> }
>
> - if ( direct_mmio )
With this gone, there's exactly one further use left. Preferably
with this adjustment (which I'd be fine to make while committing, as
long as you and/or the maintainers agree)
Reviewed-by: Jan Beulich <jbeul...@suse.com>
> + switch ( type )
> + {
> + case p2m_mmio_direct:
> return MTRR_TYPE_UNCACHABLE;
As a largely unrelated note: We really want to find a way to return
WC here for e.g. the frame buffer of graphics cards, the more that
hvm_get_mem_pinned_cacheattr() gets invoked only below from here
(unlike at initial introduction of the function, where it was called
ahead of the direct_mmio check, but still after the mfn_valid(), so
the results were inconsistent anyway). Perhaps we should obtain the
host MTRR setting for the page (or range) in question.
As to hvm_get_mem_pinned_cacheattr(), XEN_DOMCTL_pin_mem_cacheattr
is documented to be intended to be used on RAM only anyway ...
Jan
