From nobody Sun Nov 10 22:16:33 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1705999896905729.4721887821848; Tue, 23 Jan 2024 00:51:36 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rSCT7-0001bJ-3l; Tue, 23 Jan 2024 03:49:17 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rSCT5-0001b2-I0; Tue, 23 Jan 2024 03:49:15 -0500 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rSCT3-00051b-8a; Tue, 23 Jan 2024 03:49:15 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 4BC9546678; Tue, 23 Jan 2024 11:49:12 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id 02C90699F6; Tue, 23 Jan 2024 11:48:32 +0300 (MSK) Received: (nullmailer pid 3828133 invoked by uid 1000); Tue, 23 Jan 2024 08:48:31 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Mark Cave-Ayland , Guenter Roeck , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Michael Tokarev Subject: [Stable-7.2.9 19/20] hw/scsi/esp-pci: synchronise setting of DMA_STAT_DONE with ESP completion interrupt Date: Tue, 23 Jan 2024 11:48:29 +0300 Message-Id: <20240123084831.3828060-11-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1705999898160100003 From: Mark Cave-Ayland The setting of DMA_STAT_DONE at the end of a DMA transfer can be configured= to generate an interrupt, however the Linux driver manually checks for DMA_STA= T_DONE being set and if it is, considers that a DMA transfer has completed. If DMA_STAT_DONE is set but the ESP device isn't indicating an interrupt th= en the Linux driver considers this to be a spurious interrupt. However this can occur in QEMU as there is a delay between the end of DMA transfer where DMA_STAT_DONE is set, and the ESP device raising its completion interrupt. This appears to be an incorrect assumption in the Linux driver as the ESP a= nd PCI DMA interrupt sources are separate (and may not be raised exactly together), however we can work around this by synchronising the setting of DMA_STAT_DONE at the end of a DMA transfer with the ESP completion interrup= t. In conjunction with the previous commit Linux is now able to correctly boot from an am53c974 PCI SCSI device on the hppa C3700 machine without emitting "iget: checksum invalid" and "Spurious irq, sreg=3D10" errors. Signed-off-by: Mark Cave-Ayland Reviewed-by: Guenter Roeck Tested-by: Guenter Roeck Message-ID: <20240112131529.515642-4-mark.cave-ayland@ilande.co.uk> Signed-off-by: Philippe Mathieu-Daud=C3=A9 (cherry picked from commit 1e8e6644e063b20ad391140fae13d00ad7750b33) Signed-off-by: Michael Tokarev diff --git a/hw/scsi/esp-pci.c b/hw/scsi/esp-pci.c index 59ce14f843..e9e94070ec 100644 --- a/hw/scsi/esp-pci.c +++ b/hw/scsi/esp-pci.c @@ -93,6 +93,18 @@ static void esp_irq_handler(void *opaque, int irq_num, i= nt level) =20 if (level) { pci->dma_regs[DMA_STAT] |=3D DMA_STAT_SCSIINT; + + /* + * If raising the ESP IRQ to indicate end of DMA transfer, set + * DMA_STAT_DONE at the same time. In theory this should be done in + * esp_pci_dma_memory_rw(), however there is a delay between setti= ng + * DMA_STAT_DONE and the ESP IRQ arriving which is visible to the + * guest that can cause confusion e.g. Linux + */ + if ((pci->dma_regs[DMA_CMD] & DMA_CMD_MASK) =3D=3D 0x3 && + pci->dma_regs[DMA_WBC] =3D=3D 0) { + pci->dma_regs[DMA_STAT] |=3D DMA_STAT_DONE; + } } else { pci->dma_regs[DMA_STAT] &=3D ~DMA_STAT_SCSIINT; } @@ -306,9 +318,6 @@ static void esp_pci_dma_memory_rw(PCIESPState *pci, uin= t8_t *buf, int len, /* update status registers */ pci->dma_regs[DMA_WBC] -=3D len; pci->dma_regs[DMA_WAC] +=3D len; - if (pci->dma_regs[DMA_WBC] =3D=3D 0) { - pci->dma_regs[DMA_STAT] |=3D DMA_STAT_DONE; - } } =20 static void esp_pci_dma_memory_read(void *opaque, uint8_t *buf, int len) @@ -363,24 +372,13 @@ static const VMStateDescription vmstate_esp_pci_scsi = =3D { } }; =20 -static void esp_pci_command_complete(SCSIRequest *req, size_t resid) -{ - ESPState *s =3D req->hba_private; - PCIESPState *pci =3D container_of(s, PCIESPState, esp); - - esp_command_complete(req, resid); - pci->dma_regs[DMA_WBC] =3D 0; - pci->dma_regs[DMA_STAT] |=3D DMA_STAT_DONE; - esp_pci_update_irq(pci); -} - static const struct SCSIBusInfo esp_pci_scsi_info =3D { .tcq =3D false, .max_target =3D ESP_MAX_DEVS, .max_lun =3D 7, =20 .transfer_data =3D esp_transfer_data, - .complete =3D esp_pci_command_complete, + .complete =3D esp_command_complete, .cancel =3D esp_request_cancelled, }; =20 --=20 2.39.2