From: Roman Skakun <rm.skakun@gmail.com>
To: Stefano Stabellini <sstabellini@kernel.org>,
Julien Grall <julien@xen.org>,
xen-devel@lists.xenproject.org
Cc: Roman Skakun <roman_skakun@epam.com>,
Roman Skakun <rm.skakun@gmail.com>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
Andrii Anisov <andrii_anisov@epam.com>
Subject: [RFC 1/1] xen/arm: set iommu property for IOMMU-protected devices
Date: Mon, 4 Oct 2021 12:54:02 +0300 [thread overview]
Message-ID: <5b101e4e85668bbb18da83044520b0350344f408.1633106362.git.roman_skakun@epam.com> (raw)
In-Reply-To: <cover.1633106362.git.roman_skakun@epam.com>
From: Roman Skakun <roman_skakun@epam.com>
Xen is not exposing any IOMMU properties to Dom0.
So Dom0 assumes that all it's devices are not protected by IOMMU.
To make Dom0 aware of IOMMU-protected devices, we need to mark
them somehow. With this approach Dom0 Linux kernel will be able
to selectively disable swiotlb-xen fops for them which will remove
unnecessary buffer bounces.
This patch adds mechanism to describe IOMMU-protected devices by
adding `xen,behind-iommu` property to relevant device nodes in
Dom0 device tree.
Signed-off-by: Roman Skakun <roman_skakun@epam.com>
---
xen/arch/arm/domain_build.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 69fff7fc29..99e2c42b6c 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -580,6 +580,13 @@ static int __init write_properties(struct domain *d, struct kernel_info *kinfo,
return res;
}
+ if ( iommu_node && is_iommu_enabled(d) && dt_device_is_protected(node) )
+ {
+ res = fdt_property(kinfo->fdt, "xen,behind-iommu", NULL, 0);
+ if ( res )
+ return res;
+ }
+
/*
* Override the property "status" to disable the device when it's
* marked for passthrough.
--
2.27.0
next prev parent reply other threads:[~2021-10-04 9:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-04 9:54 [RFC 0/1] tag IOMMU-protected devices in Dom0 fdt Roman Skakun
2021-10-04 9:54 ` Roman Skakun [this message]
2021-10-06 12:45 ` [RFC 1/1] xen/arm: set iommu property for IOMMU-protected devices Oleksandr
2021-10-07 11:04 ` Roman Skakun
2021-11-08 18:30 ` Julien Grall
2021-11-10 21:12 ` Stefano Stabellini
2021-12-07 15:40 ` Sergiy Kibrik
2021-12-10 2:04 ` Stefano Stabellini
2021-10-04 9:54 ` [RFC PATCH] dma-mapping: don't set swiotlb-xen fops " Roman Skakun
2021-10-12 14:11 ` [RFC 0/1] tag IOMMU-protected devices in Dom0 fdt Roman Skakun
2021-10-12 14:20 ` Julien Grall
2021-10-12 14:23 ` Roman Skakun
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