On Tue, 9 Jul 2019 18:55:34 -0400 Collin Walling <wall...@linux.ibm.com> wrote:
> On 7/8/19 9:23 AM, Christian Borntraeger wrote: > > > > > > On 08.07.19 14:54, Cornelia Huck wrote: > >> According to the comment, the bits are supposed to accumulate. > >> > >> Reported-by: Stefan Weil <s...@weilnetz.de> > >> Fixes: 5d1abf234462 ("s390x/pci: enforce zPCI state checking") > >> Signed-off-by: Cornelia Huck <coh...@redhat.com> > > > > This patch does not change behaviour, so it is certainly not wrong. > > > > So lets have a look at if the bug report was actually a real bug or > > just a missing annotation. > > > >> --- > >> hw/s390x/s390-pci-inst.c | 2 ++ > >> 1 file changed, 2 insertions(+) > >> > >> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c > >> index 61f30b8e55d2..00235148bed7 100644 > >> --- a/hw/s390x/s390-pci-inst.c > >> +++ b/hw/s390x/s390-pci-inst.c > >> @@ -1209,8 +1209,10 @@ int stpcifc_service_call(S390CPU *cpu, uint8_t r1, > >> uint64_t fiba, uint8_t ar, > >> * FH Enabled bit is set to one in states of ENABLED, BLOCKED or > >> ERROR. */ > >> case ZPCI_FS_ERROR: > >> fib.fc |= 0x20; > >> + /* fallthrough */ > > > > This is correct, in case of an error we are also blocked. > > > > Agreed. This is definitely correct based on our architecture. > > >> case ZPCI_FS_BLOCKED: > >> fib.fc |= 0x40; > >> + /* fallthrough */ > > > > I think this is also correct, but it would be good if Collin could verify. > > > > I failed to find anything to support setting the function control > enabled bit when the function state is in error / blocked. I'm > assuming this might be some QEMU hack to get things working? I'll have > to dive further to understand why this was done this way, as it doesn't > align with how the s390x architecture is documented. It's confusing. Might this also be a real issue? Not matching the architecture is not a good sign... > > Functionally, this doesn't change anything... so I'll at least give it > an ACK for now and investigate this further. I prefer to hold off on this patch for now, unless we're really sure that the code does not have a problem here. Actually documenting something that might be wrong does not sound like the right thing to do :/ > > >> case ZPCI_FS_ENABLED: > >> fib.fc |= 0x80; > >> if (pbdev->iommu->enabled) { > >> > > > > > > Acked-by: Collin Walling <wall...@linux.ibm.com> > > Side note: is there somewhere that I could access this bug report? :) It's the build log with the extra warnings in https://qemu.weilnetz.de/results/build-20190708.txt (referenced in <591d71a5-5b10-ab22-4751-01da8613d...@weilnetz.de> on qemu-devel).