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| author |  Michael Kelley <mhklinux@outlook.com>
| 2024-01-15 18:20:06 -0800 |
|---|---|---|
| committer |  Wei Liu <wei.liu@kernel.org>
| 2024-03-01 08:31:41 +0000 |
| commit | 9fef276f9f416a1e85eb48d3bd38e6018a220bf5 (patch) | |
| tree | d48817edef85763486313b14c6ae7fbfd82410fc /arch/x86/mm | |
| parent | Documentation: hyperv: Add overview of PCI pass-thru device support (diff) | |
| download | linux-9fef276f9f416a1e85eb48d3bd38e6018a220bf5.tar.gz linux-9fef276f9f416a1e85eb48d3bd38e6018a220bf5.tar.bz2 linux-9fef276f9f416a1e85eb48d3bd38e6018a220bf5.zip | |
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>
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/pat/set_memory.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index e9b448d1b1b7..b28b6f8afb0e 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -755,10 +755,14 @@ pmd_t *lookup_pmd_address(unsigned long address) * areas on 32-bit NUMA systems. The percpu areas can * end up in this kind of memory, for instance. * - * This could be optimized, but it is only intended to be - * used at initialization time, and keeping it - * unoptimized should increase the testing coverage for - * the more obscure platforms. + * Note that as long as the PTEs are well-formed with correct PFNs, this + * works without checking the PRESENT bit in the leaf PTE. This is unlike + * the similar vmalloc_to_page() and derivatives. Callers may depend on + * this behavior. + * + * This could be optimized, but it is only used in paths that are not perf + * sensitive, and keeping it unoptimized should increase the testing coverage + * for the more obscure platforms. */ phys_addr_t slow_virt_to_phys(void *__virt_addr) { |