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8e5647a723
On 64-bit platforms, the pfn_to_kaddr() macro requires that the input value is 64 bits in order to ensure that valid address bits don't get lost when shifting that input by PAGE_SHIFT to calculate the physical address to provide a virtual address for. One such example is in pvalidate_pages() (used by SEV-SNP guests), where the GFN in the struct used for page-state change requests is a 40-bit bit-field, so attempts to pass this GFN field directly into pfn_to_kaddr() ends up causing guest crashes when dealing with addresses above the 1TB range due to the above. Fix this issue with SEV-SNP guests, as well as any similar cases that might cause issues in current/future code, by using an inline function, instead of a macro, so that the input is implicitly cast to the expected 64-bit input type prior to performing the shift operation. While it might be argued that the issue is on the caller side, other archs/macros have taken similar approaches to deal with instances like this, such as ARM explicitly casting the input to phys_addr_t:e48866647b("ARM: 8396/1: use phys_addr_t in pfn_to_kaddr()") A C inline function is even better though. [ mingo: Refined the changelog some more & added __always_inline. ] Fixes:6c32117963("x86/sev: Add SNP-specific unaccepted memory support") Suggested-by: Dave Hansen <dave.hansen@intel.com> Suggested-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20231122163700.400507-1-michael.roth@amd.com Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org>
96 lines
2.4 KiB
C
96 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_PAGE_H
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#define _ASM_X86_PAGE_H
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#include <linux/types.h>
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#ifdef __KERNEL__
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#include <asm/page_types.h>
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#ifdef CONFIG_X86_64
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#include <asm/page_64.h>
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#else
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#include <asm/page_32.h>
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#endif /* CONFIG_X86_64 */
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#ifndef __ASSEMBLY__
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struct page;
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#include <linux/range.h>
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extern struct range pfn_mapped[];
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extern int nr_pfn_mapped;
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static inline void clear_user_page(void *page, unsigned long vaddr,
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struct page *pg)
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{
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clear_page(page);
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}
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static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
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struct page *topage)
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{
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copy_page(to, from);
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}
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#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
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vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
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#ifndef __pa
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#define __pa(x) __phys_addr((unsigned long)(x))
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#endif
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#define __pa_nodebug(x) __phys_addr_nodebug((unsigned long)(x))
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/* __pa_symbol should be used for C visible symbols.
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This seems to be the official gcc blessed way to do such arithmetic. */
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/*
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* We need __phys_reloc_hide() here because gcc may assume that there is no
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* overflow during __pa() calculation and can optimize it unexpectedly.
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* Newer versions of gcc provide -fno-strict-overflow switch to handle this
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* case properly. Once all supported versions of gcc understand it, we can
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* remove this Voodoo magic stuff. (i.e. once gcc3.x is deprecated)
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*/
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#define __pa_symbol(x) \
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__phys_addr_symbol(__phys_reloc_hide((unsigned long)(x)))
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#ifndef __va
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#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
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#endif
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#define __boot_va(x) __va(x)
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#define __boot_pa(x) __pa(x)
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/*
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* virt_to_page(kaddr) returns a valid pointer if and only if
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* virt_addr_valid(kaddr) returns true.
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*/
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#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
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extern bool __virt_addr_valid(unsigned long kaddr);
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#define virt_addr_valid(kaddr) __virt_addr_valid((unsigned long) (kaddr))
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static __always_inline void *pfn_to_kaddr(unsigned long pfn)
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{
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return __va(pfn << PAGE_SHIFT);
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}
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static __always_inline u64 __canonical_address(u64 vaddr, u8 vaddr_bits)
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{
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return ((s64)vaddr << (64 - vaddr_bits)) >> (64 - vaddr_bits);
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}
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static __always_inline u64 __is_canonical_address(u64 vaddr, u8 vaddr_bits)
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{
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return __canonical_address(vaddr, vaddr_bits) == vaddr;
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}
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#endif /* __ASSEMBLY__ */
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#include <asm-generic/memory_model.h>
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#include <asm-generic/getorder.h>
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#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
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#endif /* __KERNEL__ */
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#endif /* _ASM_X86_PAGE_H */
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