x86/xen: do not use _PAGE_IOMAP PTE flag for I/O mappings
Since mfn_to_pfn() returns the correct PFN for identity mappings (as used for MMIO regions), the use of _PAGE_IOMAP is not required in pte_mfn_to_pfn(). Do not set the _PAGE_IOMAP flag in pte_pfn_to_mfn() and do not use it in pte_mfn_to_pfn(). This will allow _PAGE_IOMAP to be removed, making it available for future use. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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@ -399,38 +399,14 @@ static pteval_t pte_pfn_to_mfn(pteval_t val)
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if (unlikely(mfn == INVALID_P2M_ENTRY)) {
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if (unlikely(mfn == INVALID_P2M_ENTRY)) {
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mfn = 0;
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mfn = 0;
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flags = 0;
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flags = 0;
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} else {
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} else
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/*
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mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
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* Paramount to do this test _after_ the
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* INVALID_P2M_ENTRY as INVALID_P2M_ENTRY &
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* IDENTITY_FRAME_BIT resolves to true.
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*/
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mfn &= ~FOREIGN_FRAME_BIT;
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if (mfn & IDENTITY_FRAME_BIT) {
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mfn &= ~IDENTITY_FRAME_BIT;
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flags |= _PAGE_IOMAP;
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}
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}
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val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
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val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
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}
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}
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return val;
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return val;
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}
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}
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static pteval_t iomap_pte(pteval_t val)
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{
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if (val & _PAGE_PRESENT) {
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unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
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pteval_t flags = val & PTE_FLAGS_MASK;
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/* We assume the pte frame number is a MFN, so
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just use it as-is. */
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val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
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}
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return val;
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}
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__visible pteval_t xen_pte_val(pte_t pte)
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__visible pteval_t xen_pte_val(pte_t pte)
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{
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{
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pteval_t pteval = pte.pte;
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pteval_t pteval = pte.pte;
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@ -441,9 +417,6 @@ __visible pteval_t xen_pte_val(pte_t pte)
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pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT;
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pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT;
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}
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}
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#endif
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#endif
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if (xen_initial_domain() && (pteval & _PAGE_IOMAP))
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return pteval;
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return pte_mfn_to_pfn(pteval);
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return pte_mfn_to_pfn(pteval);
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}
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}
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PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
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PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
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@ -481,7 +454,6 @@ void xen_set_pat(u64 pat)
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__visible pte_t xen_make_pte(pteval_t pte)
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__visible pte_t xen_make_pte(pteval_t pte)
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{
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{
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phys_addr_t addr = (pte & PTE_PFN_MASK);
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#if 0
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#if 0
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/* If Linux is trying to set a WC pte, then map to the Xen WC.
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/* If Linux is trying to set a WC pte, then map to the Xen WC.
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* If _PAGE_PAT is set, then it probably means it is really
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* If _PAGE_PAT is set, then it probably means it is really
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@ -496,19 +468,7 @@ __visible pte_t xen_make_pte(pteval_t pte)
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pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;
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pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;
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}
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}
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#endif
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#endif
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/*
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pte = pte_pfn_to_mfn(pte);
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* Unprivileged domains are allowed to do IOMAPpings for
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* PCI passthrough, but not map ISA space. The ISA
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* mappings are just dummy local mappings to keep other
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* parts of the kernel happy.
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*/
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if (unlikely(pte & _PAGE_IOMAP) &&
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(xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
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pte = iomap_pte(pte);
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} else {
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pte &= ~_PAGE_IOMAP;
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pte = pte_pfn_to_mfn(pte);
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}
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return native_make_pte(pte);
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return native_make_pte(pte);
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}
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}
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@ -2091,7 +2051,7 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
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default:
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default:
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/* By default, set_fixmap is used for hardware mappings */
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/* By default, set_fixmap is used for hardware mappings */
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pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP));
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pte = mfn_pte(phys, prot);
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break;
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break;
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}
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}
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