[PATCH] KVM: PPC: Book3S HV: Fix reverse map real-mode address lookup with huge vmalloc
christophe.leroy at csgroup.eu
Mon May 24 02:10:54 AEST 2021
Nicholas Piggin <npiggin at gmail.com> a écrit :
> real_vmalloc_addr() does not currently work for huge vmalloc, which is
> what the reverse map can be allocated with for radix host, hash guest.
> Add huge page awareness to the function.
> Fixes: 8abddd968a30 ("powerpc/64s/radix: Enable huge vmalloc mappings")
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> arch/powerpc/kvm/book3s_hv_rm_mmu.c | 17 ++++++++++++-----
> 1 file changed, 12 insertions(+), 5 deletions(-)
> diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> index 7af7c70f1468..5f68cb5cc009 100644
> --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> @@ -26,16 +26,23 @@
> static void *real_vmalloc_addr(void *x)
> unsigned long addr = (unsigned long) x;
> + unsigned long mask;
> + int shift;
> pte_t *p;
> - * assume we don't have huge pages in vmalloc space...
> - * So don't worry about THP collapse/split. Called
> - * Only in realmode with MSR_EE = 0, hence won't need irq_save/restore.
> + * This is called only in realmode with MSR_EE = 0, hence won't need
> + * irq_save/restore around find_init_mm_pte.
> - p = find_init_mm_pte(addr, NULL);
> + p = find_init_mm_pte(addr, &shift);
> if (!p || !pte_present(*p))
> return NULL;
> - addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
> + if (!shift)
> + shift = PAGE_SHIFT;
> + mask = (1UL << shift) - 1;
> + addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & mask);
Looks strange, before we have ~MASK now we have mask without the ~
Also use PFN_PHYS() instead of open coding ?
> return __va(addr);
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