Messages in this thread | | | Subject | Re: [PATCH] iommu/amd: Fix loop timeout issue in iommu_ga_log_enable() | From | John Garry <> | Date | Mon, 31 Jan 2022 17:06:03 +0000 |
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On 31/01/2022 16:17, Joerg Roedel wrote: > From: Joerg Roedel <jroedel@suse.de> > > The polling loop for the register change in iommu_ga_log_enable() needs > to have a udelay() in it. Otherwise the CPU might be faster than the > IOMMU hardware and wrongly trigger the WARN_ON() further down the code > stream. > > Fixes: 8bda0cfbdc1a ("iommu/amd: Detect and initialize guest vAPIC log") > Signed-off-by: Joerg Roedel <jroedel@suse.de> > --- > drivers/iommu/amd/init.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c > index dc338acf3338..d2e09d53851f 100644 > --- a/drivers/iommu/amd/init.c > +++ b/drivers/iommu/amd/init.c > @@ -834,6 +834,7 @@ static int iommu_ga_log_enable(struct amd_iommu *iommu) > status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET); > if (status & (MMIO_STATUS_GALOG_RUN_MASK)) > break; > + udelay(1);
Maybe readl_relaxed_poll_timeout_atomic() could be used instead
Thanks, John
> } > > if (WARN_ON(i >= LOOP_TIMEOUT)) >
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