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Date: Mon, 21 Feb 2022 22:05:20 +0100 From: Borislav Petkov <bp@...en8.de> To: "Kirill A. Shutemov" <kirill@...temov.name> Cc: aarcange@...hat.com, ak@...ux.intel.com, dan.j.williams@...el.com, dave.hansen@...el.com, david@...hat.com, hpa@...or.com, jgross@...e.com, jmattson@...gle.com, joro@...tes.org, jpoimboe@...hat.com, kirill.shutemov@...ux.intel.com, knsathya@...nel.org, linux-kernel@...r.kernel.org, luto@...nel.org, mingo@...hat.com, pbonzini@...hat.com, peterz@...radead.org, sathyanarayanan.kuppuswamy@...ux.intel.com, sdeep@...are.com, seanjc@...gle.com, tglx@...utronix.de, tony.luck@...el.com, vkuznets@...hat.com, wanpengli@...cent.com, x86@...nel.org Subject: Re: [PATCHv3.1 2.1/2] x86/coco: Add API to handle encryption mask On Sat, Feb 19, 2022 at 03:13:05AM +0300, Kirill A. Shutemov wrote: > AMD SME/SEV uses a bit in the page table entries to indicate that the > page is encrypted and not accessible to the VMM. > > TDX uses a similar approach, but the polarity of the mask is opposite to > AMD: if the bit is set the page is accessible to VMM. > > Provide vendor-neutral API to deal with the mask: > > - cc_mkenc() and cc_mkdec() modify given address to make it > encrypted/decrypted. It can be applied to phys_addr_t, pgprotval_t > or page table entry value. > > - cc_get_mask() returns encryption or decrypthion mask. It is useful Unknown word [encrypthion] in commit message. Suggestions: ['encryption', 'decryption'] Unknown word [decrypthion] in commit message. Suggestions: ['decryption', 'encryption'] > for set_memory_encrypted() and set_memory_decrypted() > implementation. > > The implementation will be extended to cover TDX. > > pgprot_decrypted() is used by drivers (i915, virtio_gpu, vfio). > cc_mkdec() called by pgprot_decrypted(). Export cc_mkdec(). > > HyperV doesn't use bits in page table entries, so the mask is 0 for both > encrypthion and decrypthion. ditto. > diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c > index d77cf3a31f07..9af6be143998 100644 > --- a/arch/x86/kernel/cpu/mshyperv.c > +++ b/arch/x86/kernel/cpu/mshyperv.c > @@ -346,7 +346,7 @@ static void __init ms_hyperv_init_platform(void) > swiotlb_force = SWIOTLB_FORCE; > #endif > if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE) > - cc_init(CC_VENDOR_HYPERV); > + cc_init(CC_VENDOR_HYPERV, 0); > } > > if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) { > diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c > index eb7fbd85b77e..fa758247ab57 100644 > --- a/arch/x86/mm/mem_encrypt_identity.c > +++ b/arch/x86/mm/mem_encrypt_identity.c > @@ -603,5 +603,5 @@ void __init sme_enable(struct boot_params *bp) > out: > physical_mask &= ~sme_me_mask; > if (sme_me_mask) > - cc_init(CC_VENDOR_AMD); > + cc_init(CC_VENDOR_AMD, sme_me_mask); I'm wondering why this is looking weird... an init function with two arguments which get assigned. I think it would be better if you do: cc_set_vendor(CC_VENDOR_XXX); cc_set_mask(mask); and those helpers simply assign to __ro_after_init, local variables. IOW, simple setter functions. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
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