Messages in this thread | | | Date | Wed, 2 Feb 2022 22:27:10 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv2 22/29] x86/tdx: Make pages shared in ioremap() |
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On Wed, Feb 02, 2022 at 01:25:28AM +0100, Thomas Gleixner wrote: > On Mon, Jan 24 2022 at 18:02, Kirill A. Shutemov wrote: > > > In TDX guests, guest memory is protected from host access. If a guest > > performs I/O, it needs to explicitly share the I/O memory with the host. > > > > Make all ioremap()ed pages that are not backed by normal memory > > (IORES_DESC_NONE or IORES_DESC_RESERVED) mapped as shared. > > > > Since TDX memory encryption support is similar to AMD SEV architecture, > > reuse the infrastructure from AMD SEV code. > > > > Add tdx_shared_mask() interface to get the TDX guest shared bitmask. > > > > pgprot_decrypted() is used by drivers (i915, virtio_gpu, vfio). Export > > both pgprot_encrypted() and pgprot_decrypted(). > > How so? > > # git grep pgprot_encrypted > arch/x86/include/asm/pgtable.h:#define pgprot_encrypted(prot) __pgprot(__sme_set(pgprot_val(prot))) > arch/x86/mm/ioremap.c: prot = pgprot_encrypted(prot); > arch/x86/mm/ioremap.c: return encrypted_prot ? pgprot_encrypted(prot) > arch/x86/mm/mem_encrypt_amd.c: protection_map[i] = pgprot_encrypted(protection_map[i]); > arch/x86/mm/pat/set_memory.c: cpa.mask_clr = pgprot_encrypted(cpa.mask_clr); > arch/x86/platform/efi/quirks.c: pgprot_val(pgprot_encrypted(FIXMAP_PAGE_NORMAL))); > fs/proc/vmcore.c: prot = pgprot_encrypted(prot); > include/linux/pgtable.h:#ifndef pgprot_encrypted > include/linux/pgtable.h:#define pgprot_encrypted(prot) (prot) > > I cannot find any of the above mentioned subsystems in this grep > output. Neither does this patch add any users which require those > exports.
Try to grep pgprot_decrypted().
I guess we can get away not exporting pgprot_encrypted(), but this asymmetry bothers me :)
-- Kirill A. Shutemov
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