On 06.12.2022 12:17, Andrew Cooper wrote: > On 06/12/2022 04:33, Demi Marie Obenour wrote: >> --- a/xen/common/efi/boot.c >> +++ b/xen/common/efi/boot.c >> @@ -1746,21 +1746,21 @@ void __init efi_init_memory(void) >> if ( desc->Attribute & EFI_MEMORY_WB ) >> /* nothing */; > > This is an implicit 0 case which wants changing to _PAGE_WB.
Oh, yes. Demi, feel free to retain my R-b with the adjustment. >> else if ( desc->Attribute & EFI_MEMORY_WT ) >> - prot |= _PAGE_PWT | MAP_SMALL_PAGES; >> + prot |= _PAGE_WT | MAP_SMALL_PAGES; >> else if ( desc->Attribute & EFI_MEMORY_WC ) >> - prot |= _PAGE_PAT | MAP_SMALL_PAGES; >> + prot |= _PAGE_WC | MAP_SMALL_PAGES; >> else if ( desc->Attribute & (EFI_MEMORY_UC | EFI_MEMORY_UCE) ) >> - prot |= _PAGE_PWT | _PAGE_PCD | MAP_SMALL_PAGES; >> + prot |= _PAGE_UC | MAP_SMALL_PAGES; >> else if ( efi_bs_revision >= EFI_REVISION(2, 5) && >> (desc->Attribute & EFI_MEMORY_WP) ) >> - prot |= _PAGE_PAT | _PAGE_PWT | MAP_SMALL_PAGES; >> + prot |= _PAGE_WP | MAP_SMALL_PAGES; > > Unrelated to the transformation. I'm unconvinced about the correctness > of using MAP_SMALL_PAGES here. There's nothing wrong with large pages > of reduced cache-ability, Hmm, back in the 32-bit days we needed to be afraid of hardware issues in that area. Hence we had a global policy of never allowing non-WB large pages. Maybe we don't need to be concerned anymore ... > and the framebuffer is going to live in one of these regions, probably > a WC one... I very much hope it won't live anywhere there, unless you think of non- PCI devices supplying framebuffers. As long as it's described by a BAR, it better wouldn't be covered by a memory map entry. Jan
