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Re: [PATCH for-5.2] s390x/pci: fix endianness issues
From: |
Thomas Huth |
Subject: |
Re: [PATCH for-5.2] s390x/pci: fix endianness issues |
Date: |
Wed, 18 Nov 2020 10:38:00 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 |
On 18/11/2020 09.51, Cornelia Huck wrote:
> The zPCI group and function structures are big endian. However, we do
> not consistently store them as big endian locally, and are missing some
> conversions.
>
> Let's just store the structures as host endian instead and convert to
> big endian when actually handling the instructions retrieving the data.
>
> Also fix the layout of ClpReqQueryPciGrp: g is actually only 8 bit. This
> also fixes accesses on little endian hosts.
>
> Fixes: 28dc86a07299 ("s390x/pci: use a PCI Group structure")
> Fixes: 9670ee752727 ("s390x/pci: use a PCI Function structure")
> Fixes: 1e7552ff5c34 ("s390x/pci: get zPCI function info from host")
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
>
> Alternative approach to my patch from yesterday. The change is bigger,
> but the end result is arguably nicer.
Looks way better in my eyes, thanks!
[...]
> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
> index 58cd041d17fb..6c36201229f3 100644
> --- a/hw/s390x/s390-pci-inst.c
> +++ b/hw/s390x/s390-pci-inst.c
> @@ -281,7 +281,12 @@ int clp_service_call(S390CPU *cpu, uint8_t r2, uintptr_t
> ra)
> goto out;
> }
>
> - memcpy(resquery, &pbdev->zpci_fn, sizeof(*resquery));
> + stq_p(&resquery->sdma, pbdev->zpci_fn.sdma);
> + stq_p(&resquery->edma, pbdev->zpci_fn.edma);
> + stw_p(&resquery->pchid, pbdev->zpci_fn.pchid);
> + resquery->pfgid = pbdev->zpci_fn.pfgid;
> + stl_p(&resquery->fid, pbdev->zpci_fn.fid);
> + stl_p(&resquery->uid, pbdev->zpci_fn.uid);
Looking at what had been removed in 9670ee7527279, I think you likely miss
this here:
stw_p(&resquery->ug, pbdev->zpci_fn.ug)
?
> for (i = 0; i < PCI_BAR_COUNT; i++) {
> uint32_t data = pci_get_long(pbdev->pdev->config +
> @@ -313,6 +318,13 @@ int clp_service_call(S390CPU *cpu, uint8_t r2, uintptr_t
> ra)
> goto out;
> }
> memcpy(resgrp, &group->zpci_group, sizeof(ClpRspQueryPciGrp));
I think you likely could remove the memcpy now, too?
> + resgrp->fr = group->zpci_group.fr;
> + stq_p(&resgrp->dasm, group->zpci_group.dasm);
> + stq_p(&resgrp->msia, group->zpci_group.msia);
> + stw_p(&resgrp->mui, group->zpci_group.mui);
> + stw_p(&resgrp->i, group->zpci_group.i);
> + stw_p(&resgrp->maxstbl, group->zpci_group.maxstbl);
> + resgrp->version = group->zpci_group.version;
> stw_p(&resgrp->hdr.rsp, CLP_RC_OK);
> break;
> }
[...]
> diff --git a/include/hw/s390x/s390-pci-clp.h b/include/hw/s390x/s390-pci-clp.h
> index ea2b1378cd5a..96b8e3f1331b 100644
> --- a/include/hw/s390x/s390-pci-clp.h
> +++ b/include/hw/s390x/s390-pci-clp.h
> @@ -144,10 +144,10 @@ typedef struct ClpReqQueryPciGrp {
> ClpReqHdr hdr;
> uint32_t fmt;
> uint64_t reserved1;
> -#define CLP_REQ_QPCIG_MASK_PFGID 0xff
> - uint32_t g;
> - uint32_t reserved2;
> - uint64_t reserved3;
> + uint8_t reserved2[3];
> + uint8_t g;
> + uint32_t reserved3;
> + uint64_t reserved4;
> } QEMU_PACKED ClpReqQueryPciGrp;
This might even qualify as a separate patch, since it fixes a separate
problem on big endian hosts, too (g should have been masked with 0xff when
read as 32-bit value).
Thomas
- Re: [PATCH for-5.2] s390x/pci: fix endianness issues, (continued)
Re: [PATCH for-5.2] s390x/pci: fix endianness issues, Matthew Rosato, 2020/11/17
Re: [PATCH for-5.2] s390x/pci: fix endianness issues, Thomas Huth, 2020/11/17
[PATCH for-5.2] s390x/pci: fix endianness issues, Cornelia Huck, 2020/11/18