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x86/hyperv: Use slow_virt_to_phys() in page transition hypervisor callback
In preparation for temporarily marking pages not present during a transition between encrypted and decrypted, use slow_virt_to_phys() in the hypervisor callback. As long as the PFN is correct, slow_virt_to_phys() works even if the leaf PTE is not present. The existing functions that depend on vmalloc_to_page() all require that the leaf PTE be marked present, so they don't work. Update the comments for slow_virt_to_phys() to note this broader usage and the requirement to work even if the PTE is not marked present. Signed-off-by: Michael Kelley <mhklinux@outlook.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Link: https://lore.kernel.org/r/20240116022008.1023398-2-mhklinux@outlook.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Message-ID: <20240116022008.1023398-2-mhklinux@outlook.com>
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@ -515,6 +515,8 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo
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enum hv_mem_host_visibility visibility = enc ?
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VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE;
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u64 *pfn_array;
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phys_addr_t paddr;
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void *vaddr;
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int ret = 0;
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bool result = true;
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int i, pfn;
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@ -524,7 +526,15 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo
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return false;
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for (i = 0, pfn = 0; i < pagecount; i++) {
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pfn_array[pfn] = virt_to_hvpfn((void *)kbuffer + i * HV_HYP_PAGE_SIZE);
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/*
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* Use slow_virt_to_phys() because the PRESENT bit has been
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* temporarily cleared in the PTEs. slow_virt_to_phys() works
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* without the PRESENT bit while virt_to_hvpfn() or similar
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* does not.
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*/
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vaddr = (void *)kbuffer + (i * HV_HYP_PAGE_SIZE);
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paddr = slow_virt_to_phys(vaddr);
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pfn_array[pfn] = paddr >> HV_HYP_PAGE_SHIFT;
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pfn++;
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if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
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@ -755,10 +755,14 @@ pmd_t *lookup_pmd_address(unsigned long address)
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* areas on 32-bit NUMA systems. The percpu areas can
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* end up in this kind of memory, for instance.
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*
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* This could be optimized, but it is only intended to be
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* used at initialization time, and keeping it
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* unoptimized should increase the testing coverage for
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* the more obscure platforms.
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* Note that as long as the PTEs are well-formed with correct PFNs, this
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* works without checking the PRESENT bit in the leaf PTE. This is unlike
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* the similar vmalloc_to_page() and derivatives. Callers may depend on
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* this behavior.
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*
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* This could be optimized, but it is only used in paths that are not perf
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* sensitive, and keeping it unoptimized should increase the testing coverage
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* for the more obscure platforms.
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*/
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phys_addr_t slow_virt_to_phys(void *__virt_addr)
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{
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