* [PATCH] iommu/amd: Enable PCIe ACS only if AMD IOMMU is on
@ 2025-09-28 7:52 Jinhui Guo
2025-10-10 19:57 ` Suthikulpanit, Suravee
0 siblings, 1 reply; 2+ messages in thread
From: Jinhui Guo @ 2025-09-28 7:52 UTC (permalink / raw)
To: joro, suravee.suthikulpanit; +Cc: guojinhui.liam, iommu, linux-kernel
To preserve PCIe performance, ACS is enabled only when
AMD IOMMU is not disabled.
Signed-off-by: Jinhui Guo <guojinhui.liam@bytedance.com>
---
drivers/iommu/amd/init.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index ba9e582a8bbe..6e9eab365123 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -3212,8 +3212,10 @@ static bool __init detect_ivrs(void)
}
out:
- /* Make sure ACS will be enabled during PCI probe */
- pci_request_acs();
+ if (!amd_iommu_disabled || amd_iommu_force_enable) {
+ /* Make sure ACS will be enabled during PCI probe */
+ pci_request_acs();
+ }
return true;
}
--
2.20.1
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH] iommu/amd: Enable PCIe ACS only if AMD IOMMU is on
2025-09-28 7:52 [PATCH] iommu/amd: Enable PCIe ACS only if AMD IOMMU is on Jinhui Guo
@ 2025-10-10 19:57 ` Suthikulpanit, Suravee
0 siblings, 0 replies; 2+ messages in thread
From: Suthikulpanit, Suravee @ 2025-10-10 19:57 UTC (permalink / raw)
To: Jinhui Guo, joro; +Cc: iommu, linux-kernel
On 9/28/2025 2:52 AM, Jinhui Guo wrote:
> To preserve PCIe performance, ACS is enabled only when
> AMD IOMMU is not disabled.
>
> Signed-off-by: Jinhui Guo <guojinhui.liam@bytedance.com>
> ---
> drivers/iommu/amd/init.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
> index ba9e582a8bbe..6e9eab365123 100644
> --- a/drivers/iommu/amd/init.c
> +++ b/drivers/iommu/amd/init.c
> @@ -3212,8 +3212,10 @@ static bool __init detect_ivrs(void)
> }
>
> out:
> - /* Make sure ACS will be enabled during PCI probe */
> - pci_request_acs();
> + if (!amd_iommu_disabled || amd_iommu_force_enable) {
You should not need to check the amd_iommu_force_enable since it is used
only to skip a workaround logic within the same function. You can simply
just do
if (!amd_iommu_disabled)
/* Make sure ACS will be enabled during PCI probe */
pci_request_acs();
With that
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Thanks,
Suravee
> + /* Make sure ACS will be enabled during PCI probe */
> + pci_request_acs();
> + }
>
> return true;
> }
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2025-10-10 19:58 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
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2025-09-28 7:52 [PATCH] iommu/amd: Enable PCIe ACS only if AMD IOMMU is on Jinhui Guo
2025-10-10 19:57 ` Suthikulpanit, Suravee
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