lkml.org 
[lkml]   [2014]   [Feb]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] PPC: KVM: fix VCPU run for HV KVM
    On 01/13/2014 02:44 AM, Alexander Graf wrote:
    >
    > On 10.01.2014, at 08:21, Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
    >
    >> When write to MMIO happens and there is an ioeventfd for that and
    >> is handled successfully, ioeventfd_write() returns 0 (success) and
    >> kvmppc_handle_store() returns EMULATE_DONE. Then kvmppc_emulate_mmio()
    >> converts EMULATE_DONE to RESUME_GUEST_NV and this broke from the loop.
    >>
    >> This adds handling of RESUME_GUEST_NV in kvmppc_vcpu_run_hv().
    >>
    >> Cc: Michael S. Tsirkin <mst@redhat.com>
    >> Suggested-by: Paul Mackerras <paulus@samba.org>
    >> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
    >> ---
    >>
    >> This definitely needs a better commit message. Please, help.
    >> ps. it seems like ioeventfd never worked on ppc64. hm.
    >>
    >> ---
    >> arch/powerpc/kvm/book3s_hv.c | 2 +-
    >> 1 file changed, 1 insertion(+), 1 deletion(-)
    >>
    >> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
    >> index 072287f..24f363f 100644
    >> --- a/arch/powerpc/kvm/book3s_hv.c
    >> +++ b/arch/powerpc/kvm/book3s_hv.c
    >> @@ -1569,7 +1569,7 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu)
    >> vcpu->arch.fault_dar, vcpu->arch.fault_dsisr);
    >> srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx);
    >> }
    >> - } while (r == RESUME_GUEST);
    >> + } while ((r == RESUME_GUEST_NV) || (r == RESUME_GUEST));
    >
    > How about
    >
    > while(!(r & RESUME_FLAG_HOST));


    Rather "while(!(r & RESUME_FLAG_HOST) && (r > 0));" and still not obvious
    that this is really better.

    Paul agrees with the original patch (and made a better commit message for
    our internal tree) but I just cannot make him reply in this thread, keep
    constantly asking him but to no avail :)


    > That should cover all RESUME_GUEST_XXX cases just fine. Apart from that
    > I agree that we should check for ! FLAG_HOST bit rather than the actual
    > RESUME_GUEST value in all case where we check for it (read: please
    > update all places).

    There are 3 places remotely similar to this and none of them requires a fix
    like above.



    --
    Alexey


    \
     
     \ /
      Last update: 2014-02-04 09:41    [W:3.084 / U:0.016 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site