From: Nikhil Rao Date: Wed, 1 Oct 2025 01:22:26 +0000 (-0700) Subject: dmaengine: idxd: drain ATS translations when disabling WQ X-Git-Tag: v6.19-rc1~54^2~17 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f80ea8566917c4bb680911db839a170873e5d17c;p=thirdparty%2Flinux.git dmaengine: idxd: drain ATS translations when disabling WQ There's an errata[1], for the Disable WQ command that it does not guaranteee that address translations are drained. If WQ configuration is updated, pending address translations can use an updated WQ configuration, resulting an invalid translation response that is cached in the device translation cache. Replace the Disable WQ command with a Drain WQ command followed by a Reset WQ command, this guarantees that all ATS translations are drained from the device before changing WQ configuration. [1] https://cdrdv2.intel.com/v1/dl/getcontent/843306 ("Intel DSA May Cause Invalid Translation Caching") Signed-off-by: Nikhil Rao Signed-off-by: Fenghua Yu Signed-off-by: Vinicius Costa Gomes Reviewed-by: Dave Jiang Signed-off-by: Vinod Koul --- diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c index 5cf419fe6b464..c2cdf41b6e576 100644 --- a/drivers/dma/idxd/device.c +++ b/drivers/dma/idxd/device.c @@ -16,6 +16,7 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand, u32 *status); static void idxd_device_wqs_clear_state(struct idxd_device *idxd); static void idxd_wq_disable_cleanup(struct idxd_wq *wq); +static int idxd_wq_config_write(struct idxd_wq *wq); /* Interrupt control bits */ void idxd_unmask_error_interrupts(struct idxd_device *idxd) @@ -215,14 +216,28 @@ int idxd_wq_disable(struct idxd_wq *wq, bool reset_config) return 0; } + /* + * Disable WQ does not drain address translations, if WQ attributes are + * changed before translations are drained, pending translations can + * be issued using updated WQ attibutes, resulting in invalid + * translations being cached in the device translation cache. + * + * To make sure pending translations are drained before WQ + * attributes are changed, we use a WQ Drain followed by WQ Reset and + * then restore the WQ configuration. + */ + idxd_wq_drain(wq); + operand = BIT(wq->id % 16) | ((wq->id / 16) << 16); - idxd_cmd_exec(idxd, IDXD_CMD_DISABLE_WQ, operand, &status); + idxd_cmd_exec(idxd, IDXD_CMD_RESET_WQ, operand, &status); if (status != IDXD_CMDSTS_SUCCESS) { - dev_dbg(dev, "WQ disable failed: %#x\n", status); + dev_dbg(dev, "WQ reset failed: %#x\n", status); return -ENXIO; } + idxd_wq_config_write(wq); + if (reset_config) idxd_wq_disable_cleanup(wq); clear_bit(wq->id, idxd->wq_enable_map);