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dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46908 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kI9CT-0007sv-4K for qemu-devel@archiver.kernel.org; Tue, 15 Sep 2020 07:32:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34112) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kI993-0005se-Nd for qemu-devel@nongnu.org; Tue, 15 Sep 2020 07:29:09 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:26975) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kI990-0001Vz-TN for qemu-devel@nongnu.org; Tue, 15 Sep 2020 07:29:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600169344; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vFYXj3FZJso3DY0L/q/LPATkoPH742Rkb8735oLaAbg=; b=b1Qq1paqy7LiL/xyuLDoLRUA/QiknMCuZFFgYp/59WVjXncbmE0JGcr+rDZKLbhh93Ucin ZEGJOQ7rXRX/5JOdnkwpJi4BeOs/EfL2fXd4EfO6BxuPc1NYKCNiNRL/h76QJkX0cAUM+g qdtQyrSl/FVp0cSxgup8UUEmOPIOwrI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-558-lsVxycozOJOiGfmRn2vkLw-1; Tue, 15 Sep 2020 07:29:02 -0400 X-MC-Unique: lsVxycozOJOiGfmRn2vkLw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C0B1710BBED1; Tue, 15 Sep 2020 11:29:00 +0000 (UTC) Received: from gondolin (ovpn-113-4.ams2.redhat.com [10.36.113.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id AB5D6100239F; Tue, 15 Sep 2020 11:28:52 +0000 (UTC) Date: Tue, 15 Sep 2020 13:28:49 +0200 From: Cornelia Huck To: Matthew Rosato Subject: Re: [PATCH v2 2/3] s390x/pci: Honor DMA limits set by vfio Message-ID: <20200915132849.5e166b3e.cohuck@redhat.com> In-Reply-To: <1600122570-12941-3-git-send-email-mjrosato@linux.ibm.com> References: <1600122570-12941-1-git-send-email-mjrosato@linux.ibm.com> <1600122570-12941-3-git-send-email-mjrosato@linux.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=cohuck@redhat.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/15 02:23:19 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -50 X-Spam_score: -5.1 X-Spam_bar: ----- X-Spam_report: (-5.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.999, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: thuth@redhat.com, pmorel@linux.ibm.com, david@redhat.com, schnelle@linux.ibm.com, qemu-s390x@nongnu.org, qemu-devel@nongnu.org, pasic@linux.ibm.com, borntraeger@de.ibm.com, alex.williamson@redhat.com, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, 14 Sep 2020 18:29:29 -0400 Matthew Rosato wrote: > When an s390 guest is using lazy unmapping, it can result in a very > large number of oustanding DMA requests, far beyond the default > limit configured for vfio. Let's track DMA usage similar to vfio > in the host, and trigger the guest to flush their DMA mappings > before vfio runs out. > > Signed-off-by: Matthew Rosato > --- > hw/s390x/s390-pci-bus.c | 99 +++++++++++++++++++++++++++++++++++++++++++++--- > hw/s390x/s390-pci-bus.h | 9 +++++ > hw/s390x/s390-pci-inst.c | 29 +++++++++++--- > hw/s390x/s390-pci-inst.h | 3 ++ > 4 files changed, 129 insertions(+), 11 deletions(-) > (...) > @@ -737,6 +742,82 @@ static void s390_pci_iommu_free(S390pciState *s, PCIBus *bus, int32_t devfn) > object_unref(OBJECT(iommu)); > } > > +static bool s390_sync_dma_avail(int fd, unsigned int *avail) Not sure I like the name. It sounds like the function checks whether "sync dma" is available. Maybe s390_update_dma_avail()? > +{ > + struct vfio_iommu_type1_info *info; > + uint32_t argsz; > + bool rval = false; > + int ret; > + > + if (avail == NULL) { > + return false; > + } > + > + argsz = sizeof(struct vfio_iommu_type1_info); > + info = g_malloc0(argsz); > + info->argsz = argsz; > + /* > + * If the specified argsz is not large enough to contain all > + * capabilities it will be updated upon return. In this case > + * use the updated value to get the entire capability chain. > + */ > + ret = ioctl(fd, VFIO_IOMMU_GET_INFO, info); > + if (argsz != info->argsz) { > + argsz = info->argsz; > + info = g_realloc(info, argsz); > + info->argsz = argsz; > + ret = ioctl(fd, VFIO_IOMMU_GET_INFO, info); > + } > + > + if (ret) { > + goto out; > + } > + > + /* If the capability exists, update with the current value */ > + rval = vfio_get_info_dma_avail(info, avail); Adding vfio specific things into the generic s390 pci emulation code looks a bit ugly... I'd prefer to factor that out into a separate file, especially if you plan to add more vfio-specific things in the future. > + > +out: > + g_free(info); > + return rval; > +} > + (...) > diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c > index 2f7a7d7..6af9af4 100644 > --- a/hw/s390x/s390-pci-inst.c > +++ b/hw/s390x/s390-pci-inst.c > @@ -32,6 +32,9 @@ > } \ > } while (0) > > +#define INC_DMA_AVAIL(iommu) if (iommu->dma_limit) iommu->dma_limit->avail++; > +#define DEC_DMA_AVAIL(iommu) if (iommu->dma_limit) iommu->dma_limit->avail--; Hm... maybe lowercase inline functions might be better here? > + > static void s390_set_status_code(CPUS390XState *env, > uint8_t r, uint64_t status_code) > { (...) > @@ -620,6 +629,7 @@ int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra) > S390PCIIOMMU *iommu; > S390IOTLBEntry entry; > hwaddr start, end; > + uint32_t dma_avail; > > if (env->psw.mask & PSW_MASK_PSTATE) { > s390_program_interrupt(env, PGM_PRIVILEGED, ra); > @@ -675,8 +685,9 @@ int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra) > } > > start += entry.len; > - while (entry.iova < start && entry.iova < end) { > - s390_pci_update_iotlb(iommu, &entry); > + dma_avail = 1; /* Assume non-zero dma_avail to start */ > + while (entry.iova < start && entry.iova < end && dma_avail > 0) { > + dma_avail = s390_pci_update_iotlb(iommu, &entry); > entry.iova += PAGE_SIZE; > entry.translated_addr += PAGE_SIZE; > } > @@ -689,7 +700,13 @@ err: > s390_pci_generate_error_event(error, pbdev->fh, pbdev->fid, start, 0); > } else { > pbdev->fmb.counter[ZPCI_FMB_CNT_RPCIT]++; > - setcc(cpu, ZPCI_PCI_LS_OK); > + if (dma_avail > 0) { When I compile this (with a headers update), the compiler moans here about an uninitialized variable. > + setcc(cpu, ZPCI_PCI_LS_OK); > + } else { > + /* vfio DMA mappings are exhausted, trigger a RPCIT */ > + setcc(cpu, ZPCI_PCI_LS_ERR); > + s390_set_status_code(env, r1, ZPCI_RPCIT_ST_INSUFF_RES); > + } > } > return 0; > } (...)