linux-kernel - [RFC PATCH 30/30] coco/tdx_tsm: Manage TDX Module enforced operation sequences for Unbind

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Message-Id: <20250529053513.1592088-31-yilun.xu@linux.intel.com>
Date: Thu, 29 May 2025 13:35:13 +0800
From: Xu Yilun <yilun.xu@...ux.intel.com>
To: kvm@...r.kernel.org,
	sumit.semwal@...aro.org,
	christian.koenig@....com,
	pbonzini@...hat.com,
	seanjc@...gle.com,
	alex.williamson@...hat.com,
	jgg@...dia.com,
	dan.j.williams@...el.com,
	aik@....com,
	linux-coco@...ts.linux.dev
Cc: dri-devel@...ts.freedesktop.org,
	linux-media@...r.kernel.org,
	linaro-mm-sig@...ts.linaro.org,
	vivek.kasireddy@...el.com,
	yilun.xu@...el.com,
	yilun.xu@...ux.intel.com,
	linux-kernel@...r.kernel.org,
	lukas@...ner.de,
	yan.y.zhao@...el.com,
	daniel.vetter@...ll.ch,
	leon@...nel.org,
	baolu.lu@...ux.intel.com,
	zhenzhong.duan@...el.com,
	tao1.su@...el.com,
	linux-pci@...r.kernel.org,
	zhiw@...dia.com,
	simona.vetter@...ll.ch,
	shameerali.kolothum.thodi@...wei.com,
	aneesh.kumar@...nel.org,
	iommu@...ts.linux.dev,
	kevin.tian@...el.com
Subject: [RFC PATCH 30/30] coco/tdx_tsm: Manage TDX Module enforced operation sequences for Unbind

Implement TDX Connect enforced sequences for TSM unbind. The enforced
sequences are:

  1. STOP TDI via TDISP message STOP_INTERFACE
  2. Private MMIO unmap from Secure EPT
  3. Trusted Device Context Table cleanup for the TDI
  4. TDI ownership reclaim and metadata free

Step 2 is the responsibility of KVM, step 3 is for IOMMU driver. So
TDX TSM driver needs to invoke TSM handlers for external collaboration.

Signed-off-by: Xu Yilun <yilun.xu@...ux.intel.com>
---
 drivers/virt/coco/host/tdx_tsm.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/virt/coco/host/tdx_tsm.c b/drivers/virt/coco/host/tdx_tsm.c
index beb65f45b478..66d6019812ca 100644
--- a/drivers/virt/coco/host/tdx_tsm.c
+++ b/drivers/virt/coco/host/tdx_tsm.c
@@ -87,6 +87,15 @@ static struct pci_tdi *tdx_tsm_bind(struct pci_dev *pdev,
 {
 	int ret;
 
+	if (!pdev->trusted_dma_owner ||
+	    !pdev->driver->tsm_handler ||
+	    !pdev->driver->tsm_handler->disable_mmio ||
+	    !pdev->driver->tsm_handler->recover_mmio ||
+	    !pdev->driver->tsm_handler->disable_trusted_dma) {
+		pci_err(pdev, "%s no driver or driver not support bind\n", __func__);
+		return NULL;
+	}
+
 	struct tdx_tdi *ttdi __free(kfree) =
 		kzalloc(sizeof(*ttdi), GFP_KERNEL);
 	if (!ttdi)
@@ -137,15 +146,15 @@ static struct pci_tdi *tdx_tsm_bind(struct pci_dev *pdev,
 static void tdx_tsm_unbind(struct pci_tdi *tdi)
 {
 	struct tdx_tdi *ttdi = to_tdx_tdi(tdi);
+	struct pci_dev *pdev = tdi->pdev;
 
-	/*
-	 * TODO: In fact devif cannot be freed before TDI's private MMIOs and
-	 * private DMA are unmapped. Will handle this restriction later.
-	 */
 	tdx_tdi_request(ttdi, TDX_TDI_REQ_STOP);
+	pdev->driver->tsm_handler->disable_mmio(pdev);
+	pdev->driver->tsm_handler->disable_trusted_dma(pdev);
 	tdx_tdi_mmiomt_free(ttdi);
 	tdx_tdi_devif_free(ttdi);
 	tdx_tdi_devifmt_free(ttdi);
+	pdev->driver->tsm_handler->recover_mmio(pdev);
 	pci_dev_put(ttdi->tdi.dsm_dev);
 	kfree(ttdi);
 }
-- 
2.25.1