[PATCH v3 28/29] iommu/arm-smmu-v3-kvm: Allocate structures and reset device

[Mostafa Saleh]

Allocate the structures that will be shared between hypervisor and SMMU:
command queue, page table and stream table. Install them in the MMIO
registers, along with some configuration bits. After hyp initialization,
the host won't have access to those pages anymore.

Signed-off-by: Mostafa Saleh <smostafa at google.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe at linaro.org>
---
 arch/arm64/include/asm/kvm_host.h             |  5 ++
 arch/arm64/kvm/iommu.c                        |  9 ++-
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c   | 65 +++++++++++++++++++
 3 files changed, 77 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index b42e32ff2a84..37b34a9f7135 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1684,4 +1684,9 @@ int kvm_iommu_register_driver(struct kvm_iommu_driver *kern_ops, struct kvm_iomm
 int kvm_iommu_init_driver(void);
 void kvm_iommu_remove_driver(void);
 size_t kvm_iommu_pages(void);
+
+#ifdef CONFIG_ARM_SMMU_V3_PKVM
+size_t smmu_hyp_pgt_pages(void);
+#endif
+
 #endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/iommu.c b/arch/arm64/kvm/iommu.c
index 0e52cc0e18de..c4605e8001ca 100644
--- a/arch/arm64/kvm/iommu.c
+++ b/arch/arm64/kvm/iommu.c
@@ -51,10 +51,15 @@ void kvm_iommu_remove_driver(void)
 
 size_t kvm_iommu_pages(void)
 {
+	size_t nr_pages = 0;
 	/*
 	 * This is called very early during setup_arch() where no initcalls,
 	 * so this has to call specific functions per each KVM driver.
 	 */
-	kvm_nvhe_sym(hyp_kvm_iommu_pages) = 0;
-	return 0;
+#ifdef CONFIG_ARM_SMMU_V3_PKVM
+	nr_pages = smmu_hyp_pgt_pages();
+#endif
+
+	kvm_nvhe_sym(hyp_kvm_iommu_pages) = nr_pages;
+	return nr_pages;
 }
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
index 2fa56ddfbdab..2e51e211250d 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2022 Linaro Ltd.
  */
 #include <asm/kvm_mmu.h>
+#include <asm/kvm_pkvm.h>
 
 #include <linux/of_platform.h>
 
@@ -16,6 +17,7 @@ extern struct kvm_iommu_ops kvm_nvhe_sym(smmu_ops);
 struct host_arm_smmu_device {
 	struct arm_smmu_device		smmu;
 	pkvm_handle_t			id;
+	u32				boot_gbpa;
 };
 
 #define smmu_to_host(_smmu) \
@@ -65,6 +67,35 @@ static bool kvm_arm_smmu_validate_features(struct arm_smmu_device *smmu)
 	return true;
 }
 
+static int kvm_arm_smmu_device_reset(struct host_arm_smmu_device *host_smmu)
+{
+	int ret;
+	u32 reg;
+	struct arm_smmu_device *smmu = &host_smmu->smmu;
+
+	reg = readl_relaxed(smmu->base + ARM_SMMU_CR0);
+	if (reg & CR0_SMMUEN)
+		dev_warn(smmu->dev, "SMMU currently enabled! Resetting...\n");
+
+	/* Disable bypass */
+	host_smmu->boot_gbpa = readl_relaxed(smmu->base + ARM_SMMU_GBPA);
+	ret = arm_smmu_update_gbpa(smmu, GBPA_ABORT, 0);
+	if (ret)
+		return ret;
+
+	ret = arm_smmu_device_disable(smmu);
+	if (ret)
+		return ret;
+
+	/* Stream table */
+	arm_smmu_write_strtab(smmu);
+
+	/* Command queue */
+	writeq_relaxed(smmu->cmdq.q.q_base, smmu->base + ARM_SMMU_CMDQ_BASE);
+
+	return 0;
+}
+
 static int kvm_arm_smmu_probe(struct platform_device *pdev)
 {
 	int ret;
@@ -112,6 +143,20 @@ static int kvm_arm_smmu_probe(struct platform_device *pdev)
 	if (!kvm_arm_smmu_validate_features(smmu))
 		return -ENODEV;
 
+	ret = arm_smmu_init_one_queue(smmu, &smmu->cmdq.q, smmu->base,
+				      ARM_SMMU_CMDQ_PROD, ARM_SMMU_CMDQ_CONS,
+				      CMDQ_ENT_DWORDS, "cmdq");
+	if (ret)
+		return ret;
+
+	ret = arm_smmu_init_strtab(smmu);
+	if (ret)
+		return ret;
+
+	ret = kvm_arm_smmu_device_reset(host_smmu);
+	if (ret)
+		return ret;
+
 	platform_set_drvdata(pdev, smmu);
 
 	/* Hypervisor parameters */
@@ -130,6 +175,15 @@ static int kvm_arm_smmu_probe(struct platform_device *pdev)
 
 static void kvm_arm_smmu_remove(struct platform_device *pdev)
 {
+	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
+	struct host_arm_smmu_device *host_smmu = smmu_to_host(smmu);
+
+	/*
+	 * There was an error during hypervisor setup. The hyp driver may
+	 * have already enabled the device, so disable it.
+	 */
+	arm_smmu_device_disable(smmu);
+	arm_smmu_update_gbpa(smmu, host_smmu->boot_gbpa, GBPA_ABORT);
 }
 
 static const struct of_device_id arm_smmu_of_match[] = {
@@ -208,6 +262,17 @@ static void kvm_arm_smmu_v3_remove_drv(void)
 	platform_driver_unregister(&kvm_arm_smmu_driver);
 }
 
+size_t smmu_hyp_pgt_pages(void)
+{
+	/*
+	 * SMMUv3 uses the same format as stage-2 and hence have the same memory
+	 * requirements, we add extra 100 pages for L2 ste.
+	 */
+	if (of_find_compatible_node(NULL, NULL, "arm,smmu-v3"))
+		return host_s2_pgtable_pages() + 100;
+	return 0;
+}
+
 struct kvm_iommu_driver kvm_smmu_v3_ops = {
 	.init_driver = kvm_arm_smmu_v3_init_drv,
 	.remove_driver = kvm_arm_smmu_v3_remove_drv,
-- 
2.50.1.552.g942d659e1b-goog