linux-kernel - [PATCH v4 08/17] iommufd: Always setup MSI and anforce cc on kernel-managed domains

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Date:   Thu, 21 Sep 2023 00:51:29 -0700
From:   Yi Liu <yi.l.liu@...el.com>
To:     joro@...tes.org, alex.williamson@...hat.com, jgg@...dia.com,
        kevin.tian@...el.com, robin.murphy@....com,
        baolu.lu@...ux.intel.com
Cc:     cohuck@...hat.com, eric.auger@...hat.com, nicolinc@...dia.com,
        kvm@...r.kernel.org, mjrosato@...ux.ibm.com,
        chao.p.peng@...ux.intel.com, yi.l.liu@...el.com,
        yi.y.sun@...ux.intel.com, peterx@...hat.com, jasowang@...hat.com,
        shameerali.kolothum.thodi@...wei.com, lulu@...hat.com,
        suravee.suthikulpanit@....com, iommu@...ts.linux.dev,
        linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
        zhenzhong.duan@...el.com, joao.m.martins@...cle.com
Subject: [PATCH v4 08/17] iommufd: Always setup MSI and anforce cc on kernel-managed domains

From: Nicolin Chen <nicolinc@...dia.com>

Now enforce_cache_coherency and msi_cookie are kernel-managed hwpt things.
So, they should be only setup on kernel-managed domains. If the attaching
domain is a user-managed domain, redirect the hwpt to hwpt->parent to do
it correctly.

Signed-off-by: Nicolin Chen <nicolinc@...dia.com>
Co-developed-by: Yi Liu <yi.l.liu@...el.com>
Signed-off-by: Yi Liu <yi.l.liu@...el.com>
---
 drivers/iommu/iommufd/device.c       | 4 ++++
 drivers/iommu/iommufd/hw_pagetable.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index eb120f70a3e3..104dd061a2a3 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -305,12 +305,16 @@ static int iommufd_group_setup_msi(struct iommufd_group *igroup,
 	 * domain after request_irq(). If it is not done interrupts will not
 	 * work on this domain.
 	 *
+	 * Note: always set up a msi_cookie on a kernel-manage hw_pagetable.
+	 *
 	 * FIXME: This is conceptually broken for iommufd since we want to allow
 	 * userspace to change the domains, eg switch from an identity IOAS to a
 	 * DMA IOAS. There is currently no way to create a MSI window that
 	 * matches what the IRQ layer actually expects in a newly created
 	 * domain.
 	 */
+	if (hwpt->user_managed)
+		hwpt = hwpt->parent;
 	if (sw_msi_start != PHYS_ADDR_MAX && !hwpt->msi_cookie) {
 		rc = iommu_get_msi_cookie(hwpt->domain, sw_msi_start);
 		if (rc)
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index dc3e11a23acf..90fd65859e28 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -152,6 +152,10 @@ iommufd_user_managed_hwpt_alloc(struct iommufd_ctx *ictx,
 
 int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
 {
+	/* Always enforce cache coherency on a kernel-managed hw_pagetable */
+	if (hwpt->user_managed)
+		hwpt = hwpt->parent;
+
 	if (hwpt->enforce_cache_coherency)
 		return 0;
 
-- 
2.34.1