[RFC,17/45] KVM: arm64: pkvm: Add IOMMU hypercalls

Commit Message

Jean-Philippe Brucker Feb. 1, 2023, 12:53 p.m. UTC

The unprivileged host IOMMU driver forwards some of the IOMMU API calls
to the hypervisor, which installs and populates the page tables.

Note that this is not a stable ABI. Those hypercalls change with the
kernel just like internal function calls.

Signed-off-by: Jean-Philippe Brucker <[e-mail]>
---
 virt/kvm/Kconfig                        |  3 +
 arch/arm64/include/asm/kvm_asm.h        |  7 +++
 arch/arm64/kvm/hyp/include/nvhe/iommu.h | 68 ++++++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/hyp-main.c      | 77 +++++++++++++++++++++++++
 4 files changed, 155 insertions(+)

Patch

diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 9fb1ff6f19e5..99b0ddc50443 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -92,3 +92,6 @@  config KVM_XFER_TO_GUEST_WORK
 
 config HAVE_KVM_PM_NOTIFIER
        bool
+
+config KVM_IOMMU
+       bool
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 12aa0ccc3b3d..e2ced352b49c 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -81,6 +81,13 @@  enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_load,
 	__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_put,
 	__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_sync_state,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_iommu_alloc_domain,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_iommu_free_domain,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_iommu_attach_dev,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_iommu_detach_dev,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_iommu_map_pages,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_iommu_unmap_pages,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_iommu_iova_to_phys,
 };
 
 #define DECLARE_KVM_VHE_SYM(sym)	extern char sym[]
diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
index c728c8e913da..26a95717b613 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/iommu.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
@@ -2,6 +2,74 @@ 
 #ifndef __ARM64_KVM_NVHE_IOMMU_H__
 #define __ARM64_KVM_NVHE_IOMMU_H__
 
+#if IS_ENABLED(CONFIG_KVM_IOMMU)
+/* Hypercall handlers */
+int kvm_iommu_alloc_domain(pkvm_handle_t iommu_id, pkvm_handle_t domain_id,
+			   unsigned long pgd_hva);
+int kvm_iommu_free_domain(pkvm_handle_t iommu_id, pkvm_handle_t domain_id);
+int kvm_iommu_attach_dev(pkvm_handle_t iommu_id, pkvm_handle_t domain_id,
+			 u32 endpoint_id);
+int kvm_iommu_detach_dev(pkvm_handle_t iommu_id, pkvm_handle_t domain_id,
+			 u32 endpoint_id);
+int kvm_iommu_map_pages(pkvm_handle_t iommu_id, pkvm_handle_t domain_id,
+			unsigned long iova, phys_addr_t paddr, size_t pgsize,
+			size_t pgcount, int prot);
+int kvm_iommu_unmap_pages(pkvm_handle_t iommu_id, pkvm_handle_t domain_id,
+			  unsigned long iova, size_t pgsize, size_t pgcount);
+phys_addr_t kvm_iommu_iova_to_phys(pkvm_handle_t iommu_id,
+				   pkvm_handle_t domain_id, unsigned long iova);
+#else /* !CONFIG_KVM_IOMMU */
+static inline int kvm_iommu_alloc_domain(pkvm_handle_t iommu_id,
+					 pkvm_handle_t domain_id,
+					 unsigned long pgd_hva)
+{
+	return -ENODEV;
+}
+
+static inline int kvm_iommu_free_domain(pkvm_handle_t iommu_id,
+					pkvm_handle_t domain_id)
+{
+	return -ENODEV;
+}
+
+static inline int kvm_iommu_attach_dev(pkvm_handle_t iommu_id,
+				       pkvm_handle_t domain_id,
+				       u32 endpoint_id)
+{
+	return -ENODEV;
+}
+
+static inline int kvm_iommu_detach_dev(pkvm_handle_t iommu_id,
+				       pkvm_handle_t domain_id,
+				       u32 endpoint_id)
+{
+	return -ENODEV;
+}
+
+static inline int kvm_iommu_map_pages(pkvm_handle_t iommu_id,
+				      pkvm_handle_t domain_id,
+				      unsigned long iova, phys_addr_t paddr,
+				      size_t pgsize, size_t pgcount, int prot)
+{
+	return -ENODEV;
+}
+
+static inline int kvm_iommu_unmap_pages(pkvm_handle_t iommu_id,
+					pkvm_handle_t domain_id,
+					unsigned long iova, size_t pgsize,
+					size_t pgcount)
+{
+	return 0;
+}
+
+static inline phys_addr_t kvm_iommu_iova_to_phys(pkvm_handle_t iommu_id,
+						 pkvm_handle_t domain_id,
+						 unsigned long iova)
+{
+	return 0;
+}
+#endif /* CONFIG_KVM_IOMMU */
+
 struct kvm_iommu_ops {
 	int (*init)(void);
 };
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 37e308337fec..34ec46b890f0 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -1059,6 +1059,76 @@  static void handle___pkvm_teardown_vm(struct kvm_cpu_context *host_ctxt)
 	cpu_reg(host_ctxt, 1) = __pkvm_teardown_vm(handle);
 }
 
+static void handle___pkvm_host_iommu_alloc_domain(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, iommu, host_ctxt, 1);
+	DECLARE_REG(pkvm_handle_t, domain, host_ctxt, 2);
+	DECLARE_REG(unsigned long, pgd_hva, host_ctxt, 3);
+
+	cpu_reg(host_ctxt, 1) = kvm_iommu_alloc_domain(iommu, domain, pgd_hva);
+}
+
+static void handle___pkvm_host_iommu_free_domain(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, iommu, host_ctxt, 1);
+	DECLARE_REG(pkvm_handle_t, domain, host_ctxt, 2);
+
+	cpu_reg(host_ctxt, 1) = kvm_iommu_free_domain(iommu, domain);
+}
+
+static void handle___pkvm_host_iommu_attach_dev(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, iommu, host_ctxt, 1);
+	DECLARE_REG(pkvm_handle_t, domain, host_ctxt, 2);
+	DECLARE_REG(unsigned int, endpoint, host_ctxt, 3);
+
+	cpu_reg(host_ctxt, 1) = kvm_iommu_attach_dev(iommu, domain, endpoint);
+}
+
+static void handle___pkvm_host_iommu_detach_dev(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, iommu, host_ctxt, 1);
+	DECLARE_REG(pkvm_handle_t, domain, host_ctxt, 2);
+	DECLARE_REG(unsigned int, endpoint, host_ctxt, 3);
+
+	cpu_reg(host_ctxt, 1) = kvm_iommu_detach_dev(iommu, domain, endpoint);
+}
+
+static void handle___pkvm_host_iommu_map_pages(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, iommu, host_ctxt, 1);
+	DECLARE_REG(pkvm_handle_t, domain, host_ctxt, 2);
+	DECLARE_REG(unsigned long, iova, host_ctxt, 3);
+	DECLARE_REG(phys_addr_t, paddr, host_ctxt, 4);
+	DECLARE_REG(size_t, pgsize, host_ctxt, 5);
+	DECLARE_REG(size_t, pgcount, host_ctxt, 6);
+	DECLARE_REG(unsigned int, prot, host_ctxt, 7);
+
+	cpu_reg(host_ctxt, 1) = kvm_iommu_map_pages(iommu, domain, iova, paddr,
+						    pgsize, pgcount, prot);
+}
+
+static void handle___pkvm_host_iommu_unmap_pages(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, iommu, host_ctxt, 1);
+	DECLARE_REG(pkvm_handle_t, domain, host_ctxt, 2);
+	DECLARE_REG(unsigned long, iova, host_ctxt, 3);
+	DECLARE_REG(size_t, pgsize, host_ctxt, 4);
+	DECLARE_REG(size_t, pgcount, host_ctxt, 5);
+
+	cpu_reg(host_ctxt, 1) = kvm_iommu_unmap_pages(iommu, domain, iova,
+						      pgsize, pgcount);
+}
+
+static void handle___pkvm_host_iommu_iova_to_phys(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, iommu, host_ctxt, 1);
+	DECLARE_REG(pkvm_handle_t, domain, host_ctxt, 2);
+	DECLARE_REG(unsigned long, iova, host_ctxt, 3);
+
+	cpu_reg(host_ctxt, 1) = kvm_iommu_iova_to_phys(iommu, domain, iova);
+}
+
 typedef void (*hcall_t)(struct kvm_cpu_context *);
 
 #define HANDLE_FUNC(x)	[__KVM_HOST_SMCCC_FUNC_##x] = (hcall_t)handle_##x
@@ -1093,6 +1163,13 @@  static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__pkvm_vcpu_load),
 	HANDLE_FUNC(__pkvm_vcpu_put),
 	HANDLE_FUNC(__pkvm_vcpu_sync_state),
+	HANDLE_FUNC(__pkvm_host_iommu_alloc_domain),
+	HANDLE_FUNC(__pkvm_host_iommu_free_domain),
+	HANDLE_FUNC(__pkvm_host_iommu_attach_dev),
+	HANDLE_FUNC(__pkvm_host_iommu_detach_dev),
+	HANDLE_FUNC(__pkvm_host_iommu_map_pages),
+	HANDLE_FUNC(__pkvm_host_iommu_unmap_pages),
+	HANDLE_FUNC(__pkvm_host_iommu_iova_to_phys),
 };
 
 static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)