Messages in this thread | | | Date | Thu, 26 May 2022 11:38:59 -0300 | From | Wander Lairson Costa <> | Subject | Re: [PATCH v7 4/5] x86/mm: Add noalias variants of set_memory_*crypted() functions |
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On Mon, May 23, 2022 at 09:05:16PM -0700, Kuppuswamy Sathyanarayanan wrote: > set_memory_*crypted() functions are used to modify the "shared" page > attribute of the given memory. Using these APIs will modify the page > attributes of the aliased mappings (which also includes the direct > mapping). > > But such aliased mappings modification is not desirable in use cases > like TDX guest, where the requirement is to create the shared mapping > without touching the direct map. It is used when allocating VMM shared > buffers using alloc_pages()/vmap()/set_memory_*crypted() API > combinations. > > So to support such use cases, add support for noalias variants of > set_memory_*crypted() functions. > > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > --- > arch/x86/include/asm/set_memory.h | 2 ++ > arch/x86/mm/pat/set_memory.c | 26 ++++++++++++++++++++------ > 2 files changed, 22 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h > index 78ca53512486..0e5fc2b818be 100644 > --- a/arch/x86/include/asm/set_memory.h > +++ b/arch/x86/include/asm/set_memory.h > @@ -46,7 +46,9 @@ int set_memory_wb(unsigned long addr, int numpages); > int set_memory_np(unsigned long addr, int numpages); > int set_memory_4k(unsigned long addr, int numpages); > int set_memory_encrypted(unsigned long addr, int numpages); > +int set_memory_encrypted_noalias(unsigned long addr, int numpages); > int set_memory_decrypted(unsigned long addr, int numpages); > +int set_memory_decrypted_noalias(unsigned long addr, int numpages); > int set_memory_np_noalias(unsigned long addr, int numpages); > int set_memory_nonglobal(unsigned long addr, int numpages); > int set_memory_global(unsigned long addr, int numpages); > diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c > index 0656db33574d..4475f6e3bebb 100644 > --- a/arch/x86/mm/pat/set_memory.c > +++ b/arch/x86/mm/pat/set_memory.c > @@ -1976,7 +1976,8 @@ int set_memory_global(unsigned long addr, int numpages) > * __set_memory_enc_pgtable() is used for the hypervisors that get > * informed about "encryption" status via page tables. > */ > -static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc) > +static int __set_memory_enc_pgtable(unsigned long addr, int numpages, > + bool enc, int checkalias) > { > pgprot_t empty = __pgprot(0); > struct cpa_data cpa; > @@ -2004,7 +2005,7 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc) > /* Notify hypervisor that we are about to set/clr encryption attribute. */ > x86_platform.guest.enc_status_change_prepare(addr, numpages, enc); > > - ret = __change_page_attr_set_clr(&cpa, 1); > + ret = __change_page_attr_set_clr(&cpa, checkalias); > > /* > * After changing the encryption attribute, we need to flush TLBs again > @@ -2024,29 +2025,42 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc) > return ret; > } > > -static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc) > +static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc, > + int checkalias) > { > if (hv_is_isolation_supported()) > return hv_set_mem_host_visibility(addr, numpages, !enc); > > if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) > - return __set_memory_enc_pgtable(addr, numpages, enc); > + return __set_memory_enc_pgtable(addr, numpages, enc, checkalias); > > return 0; > } > > int set_memory_encrypted(unsigned long addr, int numpages) > { > - return __set_memory_enc_dec(addr, numpages, true); > + return __set_memory_enc_dec(addr, numpages, true, 1); > } > EXPORT_SYMBOL_GPL(set_memory_encrypted); > > int set_memory_decrypted(unsigned long addr, int numpages) > { > - return __set_memory_enc_dec(addr, numpages, false); > + return __set_memory_enc_dec(addr, numpages, false, 1); > } > EXPORT_SYMBOL_GPL(set_memory_decrypted); > > +int set_memory_encrypted_noalias(unsigned long addr, int numpages) > +{ > + return __set_memory_enc_dec(addr, numpages, true, 0); > +} > +EXPORT_SYMBOL_GPL(set_memory_encrypted_noalias); > + > +int set_memory_decrypted_noalias(unsigned long addr, int numpages) > +{ > + return __set_memory_enc_dec(addr, numpages, false, 0); > +} > +EXPORT_SYMBOL_GPL(set_memory_decrypted_noalias); > + > int set_pages_uc(struct page *page, int numpages) > { > unsigned long addr = (unsigned long)page_address(page); > -- > 2.25.1 > >
Acked-by: Wander Lairson Costa <wander@redhat.com>
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