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Re: [Xen-devel] [PATCH] x86/p2m: drop p2m_access_t parameter from set_mmio_p2m_entry()

On 06.02.2020 16:20, Jan Beulich wrote:
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -3037,9 +3037,8 @@ static int vmx_alloc_vlapic_mapping(stru
>      share_xen_page_with_guest(pg, d, SHARE_rw);
>      d->arch.hvm.vmx.apic_access_mfn = mfn;
> -    return set_mmio_p2m_entry(d, paddr_to_pfn(APIC_DEFAULT_PHYS_BASE), mfn,
> -                              PAGE_ORDER_4K,
> -                              p2m_get_hostp2m(d)->default_access);
> +    return set_mmio_p2m_entry(d, gaddr_to_gfn(APIC_DEFAULT_PHYS_BASE), mfn,
> +                              PAGE_ORDER_4K);
>  }

Upon 2nd thought - does this really want to use default access?
Execute permission for this page looks a little suspicious.
Isn't it the case that this page doesn't (normally?) get
accessed at all, and instead its address serves as an indicator
to the CPU? (I even vaguely recall it having been considered to
consolidate this, to e.g. a single page per domain.) In which
case even p2m_access_n might be good enough?


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