| Message ID | 20180314165049.30105-11-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 14/03/18 16:50, Marc Zyngier wrote: > Although the idmap section of KVM can only be at most 4kB and > must be aligned on a 4kB boundary, the rest of the code expects > it to be page aligned. Things get messy when tearing down the > HYP page tables when PAGE_SIZE is 64K, and the idmap section isn't > 64K aligned. > > Let's fix this by computing aligned boundaries that the HYP code > will use. > diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c > index 0e5cfffb4c21..a9e0513868e9 100644 > --- a/virt/kvm/arm/mmu.c > +++ b/virt/kvm/arm/mmu.c > @@ -1815,7 +1815,9 @@ int kvm_mmu_init(void) > int err; > > hyp_idmap_start = kvm_virt_to_phys(__hyp_idmap_text_start); > + hyp_idmap_start = ALIGN_DOWN(hyp_idmap_start, PAGE_SIZE); > hyp_idmap_end = kvm_virt_to_phys(__hyp_idmap_text_end); > + hyp_idmap_end = ALIGN(hyp_idmap_end, PAGE_SIZE); > hyp_idmap_vector = kvm_virt_to_phys(__kvm_hyp_init); > > /* This makes the: | hyp_idmap_start != (unsigned long)__hyp_idmap_text_start check below look funny, but that must be for 32bit which only has 4K pages (I think), so its behaviour hasn't changed. Reviewed-by: James Morse <james.morse@arm.com> Thanks, James
On 15/03/18 19:15, James Morse wrote: > On 14/03/18 16:50, Marc Zyngier wrote: >> Although the idmap section of KVM can only be at most 4kB and >> must be aligned on a 4kB boundary, the rest of the code expects >> it to be page aligned. Things get messy when tearing down the >> HYP page tables when PAGE_SIZE is 64K, and the idmap section isn't >> 64K aligned. >> >> Let's fix this by computing aligned boundaries that the HYP code >> will use. > >> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c >> index 0e5cfffb4c21..a9e0513868e9 100644 >> --- a/virt/kvm/arm/mmu.c >> +++ b/virt/kvm/arm/mmu.c >> @@ -1815,7 +1815,9 @@ int kvm_mmu_init(void) >> int err; >> >> hyp_idmap_start = kvm_virt_to_phys(__hyp_idmap_text_start); >> + hyp_idmap_start = ALIGN_DOWN(hyp_idmap_start, PAGE_SIZE); >> hyp_idmap_end = kvm_virt_to_phys(__hyp_idmap_text_end); >> + hyp_idmap_end = ALIGN(hyp_idmap_end, PAGE_SIZE); >> hyp_idmap_vector = kvm_virt_to_phys(__kvm_hyp_init); >> >> /* > > > This makes the: > | hyp_idmap_start != (unsigned long)__hyp_idmap_text_start > > check below look funny, but that must be for 32bit which only has 4K pages (I > think), so its behaviour hasn't changed. Yes, that's to handle the 2/2 split on 32bit where some funnies may happen, see d2896d4b55b2 ("arm: KVM: Fix idmap overlap detection when the kernel is idmap'ed"). > Reviewed-by: James Morse <james.morse@arm.com> Thanks, M.
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 0e5cfffb4c21..a9e0513868e9 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1815,7 +1815,9 @@ int kvm_mmu_init(void) int err; hyp_idmap_start = kvm_virt_to_phys(__hyp_idmap_text_start); + hyp_idmap_start = ALIGN_DOWN(hyp_idmap_start, PAGE_SIZE); hyp_idmap_end = kvm_virt_to_phys(__hyp_idmap_text_end); + hyp_idmap_end = ALIGN(hyp_idmap_end, PAGE_SIZE); hyp_idmap_vector = kvm_virt_to_phys(__kvm_hyp_init); /*
Although the idmap section of KVM can only be at most 4kB and must be aligned on a 4kB boundary, the rest of the code expects it to be page aligned. Things get messy when tearing down the HYP page tables when PAGE_SIZE is 64K, and the idmap section isn't 64K aligned. Let's fix this by computing aligned boundaries that the HYP code will use. Reported-by: James Morse <james.morse@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- virt/kvm/arm/mmu.c | 2 ++ 1 file changed, 2 insertions(+)