From patchwork Wed Apr 10 07:21:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Tokarev X-Patchwork-Id: 13623674 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B69A9CD1296 for ; Wed, 10 Apr 2024 07:25:14 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ruSJC-0008LF-Nh; Wed, 10 Apr 2024 03:23:52 -0400 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 1ruSJ6-0008Ip-S0; Wed, 10 Apr 2024 03:23:44 -0400 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 1ruSIx-0003w5-UB; Wed, 10 Apr 2024 03:23:44 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 24F9C5D67A; Wed, 10 Apr 2024 10:25:03 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id BB625B02BB; Wed, 10 Apr 2024 10:23:04 +0300 (MSK) Received: (nullmailer pid 4191677 invoked by uid 1000); Wed, 10 Apr 2024 07:23:04 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Sven Schnelle , Peter Maydell , Paolo Bonzini , Michael Tokarev Subject: [Stable-8.2.3 11/87] hw/scsi/lsi53c895a: add timer to scripts processing Date: Wed, 10 Apr 2024 10:21:44 +0300 Message-Id: <20240410072303.4191455-11-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Sven Schnelle HP-UX 10.20 seems to make the lsi53c895a spinning on a memory location under certain circumstances. As the SCSI controller and CPU are not running at the same time this loop will never finish. After some time, the check loop interrupts with a unexpected device disconnect. This works, but is slow because the kernel resets the scsi controller. Instead of signaling UDC, start a timer and exit the loop. Until the timer fires, the CPU can process instructions which might changes the memory location. The limit of instructions is also reduced because scripts running on the SCSI processor are usually very short. This keeps the time until the loop is exit short. Suggested-by: Peter Maydell Signed-off-by: Sven Schnelle Message-ID: <20240229204407.1699260-1-svens@stackframe.org> Signed-off-by: Paolo Bonzini (cherry picked from commit 9876359990dd4c8a48de65cf5e1c3d13e96a7f4e) Signed-off-by: Michael Tokarev diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c index 46c17b320e..4d0c5fcd9b 100644 --- a/hw/scsi/lsi53c895a.c +++ b/hw/scsi/lsi53c895a.c @@ -188,7 +188,7 @@ static const char *names[] = { #define LSI_TAG_VALID (1 << 16) /* Maximum instructions to process. */ -#define LSI_MAX_INSN 10000 +#define LSI_MAX_INSN 100 typedef struct lsi_request { SCSIRequest *req; @@ -205,6 +205,7 @@ enum { LSI_WAIT_RESELECT, /* Wait Reselect instruction has been issued */ LSI_DMA_SCRIPTS, /* processing DMA from lsi_execute_script */ LSI_DMA_IN_PROGRESS, /* DMA operation is in progress */ + LSI_WAIT_SCRIPTS, /* SCRIPTS stopped because of instruction count limit */ }; enum { @@ -224,6 +225,7 @@ struct LSIState { MemoryRegion ram_io; MemoryRegion io_io; AddressSpace pci_io_as; + QEMUTimer *scripts_timer; int carry; /* ??? Should this be an a visible register somewhere? */ int status; @@ -415,6 +417,7 @@ static void lsi_soft_reset(LSIState *s) s->sbr = 0; assert(QTAILQ_EMPTY(&s->queue)); assert(!s->current); + timer_del(s->scripts_timer); } static int lsi_dma_40bit(LSIState *s) @@ -1135,6 +1138,12 @@ static void lsi_wait_reselect(LSIState *s) } } +static void lsi_scripts_timer_start(LSIState *s) +{ + trace_lsi_scripts_timer_start(); + timer_mod(s->scripts_timer, qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + 500); +} + static void lsi_execute_script(LSIState *s) { PCIDevice *pci_dev = PCI_DEVICE(s); @@ -1144,6 +1153,11 @@ static void lsi_execute_script(LSIState *s) int insn_processed = 0; static int reentrancy_level; + if (s->waiting == LSI_WAIT_SCRIPTS) { + timer_del(s->scripts_timer); + s->waiting = LSI_NOWAIT; + } + reentrancy_level++; s->istat1 |= LSI_ISTAT1_SRUN; @@ -1151,8 +1165,8 @@ again: /* * Some windows drivers make the device spin waiting for a memory location * to change. If we have executed more than LSI_MAX_INSN instructions then - * assume this is the case and force an unexpected device disconnect. This - * is apparently sufficient to beat the drivers into submission. + * assume this is the case and start a timer. Until the timer fires, the + * host CPU has a chance to run and change the memory location. * * Another issue (CVE-2023-0330) can occur if the script is programmed to * trigger itself again and again. Avoid this problem by stopping after @@ -1160,13 +1174,8 @@ again: * which should be enough for all valid use cases). */ if (++insn_processed > LSI_MAX_INSN || reentrancy_level > 8) { - if (!(s->sien0 & LSI_SIST0_UDC)) { - qemu_log_mask(LOG_GUEST_ERROR, - "lsi_scsi: inf. loop with UDC masked"); - } - lsi_script_scsi_interrupt(s, LSI_SIST0_UDC, 0); - lsi_disconnect(s); - trace_lsi_execute_script_stop(); + s->waiting = LSI_WAIT_SCRIPTS; + lsi_scripts_timer_start(s); reentrancy_level--; return; } @@ -2205,6 +2214,9 @@ static int lsi_post_load(void *opaque, int version_id) return -EINVAL; } + if (s->waiting == LSI_WAIT_SCRIPTS) { + lsi_scripts_timer_start(s); + } return 0; } @@ -2302,6 +2314,15 @@ static const struct SCSIBusInfo lsi_scsi_info = { .cancel = lsi_request_cancelled }; +static void scripts_timer_cb(void *opaque) +{ + LSIState *s = opaque; + + trace_lsi_scripts_timer_triggered(); + s->waiting = LSI_NOWAIT; + lsi_execute_script(s); +} + static void lsi_scsi_realize(PCIDevice *dev, Error **errp) { LSIState *s = LSI53C895A(dev); @@ -2321,6 +2342,7 @@ static void lsi_scsi_realize(PCIDevice *dev, Error **errp) "lsi-ram", 0x2000); memory_region_init_io(&s->io_io, OBJECT(s), &lsi_io_ops, s, "lsi-io", 256); + s->scripts_timer = timer_new_us(QEMU_CLOCK_VIRTUAL, scripts_timer_cb, s); /* * Since we use the address-space API to interact with ram_io, disable the @@ -2345,6 +2367,7 @@ static void lsi_scsi_exit(PCIDevice *dev) LSIState *s = LSI53C895A(dev); address_space_destroy(&s->pci_io_as); + timer_del(s->scripts_timer); } static void lsi_class_init(ObjectClass *klass, void *data) diff --git a/hw/scsi/trace-events b/hw/scsi/trace-events index bdd4e2c7c7..5f4f4c54bb 100644 --- a/hw/scsi/trace-events +++ b/hw/scsi/trace-events @@ -301,6 +301,8 @@ lsi_execute_script_stop(void) "SCRIPTS execution stopped" lsi_awoken(void) "Woken by SIGP" lsi_reg_read(const char *name, int offset, uint8_t ret) "Read reg %s 0x%x = 0x%02x" lsi_reg_write(const char *name, int offset, uint8_t val) "Write reg %s 0x%x = 0x%02x" +lsi_scripts_timer_triggered(void) "SCRIPTS timer triggered" +lsi_scripts_timer_start(void) "SCRIPTS timer started" # virtio-scsi.c virtio_scsi_cmd_req(int lun, uint32_t tag, uint8_t cmd) "virtio_scsi_cmd_req lun=%u tag=0x%x cmd=0x%x"