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  1. 12 5月, 2017 2 次提交
    • P
      KVM: PPC: Book3S PR: Check copy_to/from_user return values · 67325e98
      由 Paul Mackerras 提交于 
      The PR KVM implementation of the PAPR HPT hypercalls (H_ENTER etc.)
access an image of the HPT in userspace memory using copy_from_user
and copy_to_user.  Recently, the declarations of those functions were
annotated to indicate that the return value must be checked.  Since
this code doesn't currently check the return value, this causes
compile warnings like the ones shown below, and since on PPC the
default is to compile arch/powerpc with -Werror, this causes the
build to fail.

To fix this, we check the return values, and if non-zero, fail the
hypercall being processed with a H_FUNCTION error return value.
There is really no good error return value to use since PAPR didn't
envisage the possibility that the hypervisor may not be able to access
the guest's HPT, and H_FUNCTION (function not supported) seems as
good as any.

The typical compile warnings look like this:

  CC      arch/powerpc/kvm/book3s_pr_papr.o
/home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c: In function ‘kvmppc_h_pr_enter’:
/home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c:53:2: error: ignoring return value of ‘copy_from_user’, declared with attribute warn_unused_result [-Werror=unused-result]
  copy_from_user(pteg, (void __user *)pteg_addr, sizeof(pteg));
  ^
/home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c:74:2: error: ignoring return value of ‘copy_to_user’, declared with attribute warn_unused_result [-Werror=unused-result]
  copy_to_user((void __user *)pteg_addr, hpte, HPTE_SIZE);
  ^

... etc.
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      67325e98
    • P
      KVM: PPC: Book3S HV: Add radix checks in real-mode hypercall handlers · acde2572
      由 Paul Mackerras 提交于 
      POWER9 running a radix guest will take some hypervisor interrupts
without going to real mode (turning off the MMU).  This means that
early hypercall handlers may now be called in virtual mode.  Most of
the handlers work just fine in both modes, but there are some that
can crash the host if called in virtual mode, notably the TCE (IOMMU)
hypercalls H_PUT_TCE, H_STUFF_TCE and H_PUT_TCE_INDIRECT.  These
already have both a real-mode and a virtual-mode version, so we
arrange for the real-mode version to return H_TOO_HARD for radix
guests, which will result in the virtual-mode version being called.

The other hypercall which is sensitive to the MMU mode is H_RANDOM.
It doesn't have a virtual-mode version, so this adds code to enable
it to be called in either mode.

An alternative solution was considered which would refuse to call any
of the early hypercall handlers when doing a virtual-mode exit from a
radix guest.  However, the XICS-on-XIVE code depends on the XICS
hypercalls being handled early even for virtual-mode exits, because
the handlers need to be called before the XIVE vCPU state has been
pulled off the hardware.  Therefore that solution would have become
quite invasive and complicated, and was rejected in favour of the
simpler, though less elegant, solution presented here.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Tested-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      acde2572
  3. 09 5月, 2017 20 次提交
  5. 08 5月, 2017 3 次提交
  7. 05 5月, 2017 2 次提交
  9. 04 5月, 2017 2 次提交
  11. 03 5月, 2017 11 次提交