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KVM: PPC: Book3S HV: Add sanity check to copy_tofrom_guest

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Both paths into __kvmhv_copy_tofrom_guest_radix ensure that we arrive
with an effective address that is smaller than our total addressable
space and addresses quadrant 0.

- The H_COPY_TOFROM_GUEST hypercall path rejects the call with
H_PARAMETER if the effective address has any of the twelve most
significant bits set.

- The kvmhv_copy_tofrom_guest_radix path clears the top twelve bits
before calling the internal function.

Although the callers make sure that the effective address is sane, any
future use of the function is exposed to a programming error, so add a
sanity check.

Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210805212616.2641017-3-farosas@linux.ibm.com
This commit is contained in:
Fabiano Rosas 2021-08-05 18:26:15 -03:00 committed by Michael Ellerman
parent 5d7d6dac8f
commit c232461c0c
1 changed files with 3 additions and 0 deletions
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3
arch/powerpc/kvm/book3s_64_mmu_radix.c
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@ -44,6 +44,9 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid,
(to != NULL) ? __pa(to): 0,
(from != NULL) ? __pa(from): 0, n);
if (eaddr & (0xFFFUL << 52))
return ret;
quadrant = 1;
if (!pid)
quadrant = 2;