[PATCH v1 17/26] x86/virt/tdx: Add SEAMCALL wrappers for trusted IOMMU setup and clear

[Xu Yilun <yilun.xu@linux.intel.com>]

From: Zhenzhong Duan <zhenzhong.duan@intel.com>

Add SEAMCALLs to setup/clear trusted IOMMU for TDX Connect.

Enable TEE I/O support for a target device requires to setup trusted IOMMU
for the related IOMMU device first, even only for enabling physical secure
links like SPDM/IDE.

TDH.IOMMU.SETUP takes the register base address (VTBAR) to position an
IOMMU device, and outputs an IOMMU_ID as the trusted IOMMU identifier.
TDH.IOMMU.CLEAR takes the IOMMU_ID to reverse the setup.

More information see Intel TDX Connect ABI Specification [1]
Section 3.2 TDX Connect Host-Side (SEAMCALL) Interface Functions.

[1]: https://cdrdv2.intel.com/v1/dl/getContent/858625

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Co-developed-by: Xu Yilun <yilun.xu@linux.intel.com>
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/x86/include/asm/tdx.h  |  2 ++
 arch/x86/virt/vmx/tdx/tdx.h |  2 ++
 arch/x86/virt/vmx/tdx/tdx.c | 32 ++++++++++++++++++++++++++++++--
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index 4078fc497779..efc4200b9931 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -225,6 +225,8 @@ u64 tdh_mem_page_remove(struct tdx_td *td, u64 gpa, u64 level, u64 *ext_err1, u6
 u64 tdh_phymem_cache_wb(bool resume);
 u64 tdh_phymem_page_wbinvd_tdr(struct tdx_td *td);
 u64 tdh_phymem_page_wbinvd_hkid(u64 hkid, struct page *page);
+u64 tdh_iommu_setup(u64 vtbar, struct tdx_page_array *iommu_mt, u64 *iommu_id);
+u64 tdh_iommu_clear(u64 iommu_id, struct tdx_page_array *iommu_mt);
 #else
 static inline void tdx_init(void) { }
 static inline int tdx_enable_ext(void) { return -ENODEV; }
diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
index b84678165d00..7c653604271b 100644
--- a/arch/x86/virt/vmx/tdx/tdx.h
+++ b/arch/x86/virt/vmx/tdx/tdx.h
@@ -48,6 +48,8 @@
 #define TDH_SYS_CONFIG			45
 #define TDH_EXT_INIT			60
 #define TDH_EXT_MEM_ADD			61
+#define TDH_IOMMU_SETUP			128
+#define TDH_IOMMU_CLEAR			129
 
 /*
  * SEAMCALL leaf:
diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index 7bc2c900a8a8..fe3b43c86314 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -2003,8 +2003,8 @@ static inline u64 tdx_tdr_pa(struct tdx_td *td)
 	return page_to_phys(td->tdr_page);
 }
 
-static u64 __maybe_unused __seamcall_ir_resched(sc_func_t sc_func, u64 fn,
-						struct tdx_module_args *args)
+static u64 __seamcall_ir_resched(sc_func_t sc_func, u64 fn,
+				 struct tdx_module_args *args)
 {
 	struct tdx_module_args _args;
 	u64 r;
@@ -2397,3 +2397,31 @@ void tdx_cpu_flush_cache_for_kexec(void)
 }
 EXPORT_SYMBOL_GPL(tdx_cpu_flush_cache_for_kexec);
 #endif
+
+u64 tdh_iommu_setup(u64 vtbar, struct tdx_page_array *iommu_mt, u64 *iommu_id)
+{
+	struct tdx_module_args args = {
+		.rcx = vtbar,
+		.rdx = page_to_phys(iommu_mt->root),
+	};
+	u64 r;
+
+	tdx_clflush_page_array(iommu_mt);
+
+	r = seamcall_ret_ir_resched(TDH_IOMMU_SETUP, &args);
+
+	*iommu_id = args.rcx;
+	return r;
+}
+EXPORT_SYMBOL_FOR_MODULES(tdh_iommu_setup, "tdx-host");
+
+u64 tdh_iommu_clear(u64 iommu_id, struct tdx_page_array *iommu_mt)
+{
+	struct tdx_module_args args = {
+		.rcx = iommu_id,
+		.rdx = page_to_phys(iommu_mt->root),
+	};
+
+	return seamcall_ret_ir_resched(TDH_IOMMU_CLEAR, &args);
+}
+EXPORT_SYMBOL_FOR_MODULES(tdh_iommu_clear, "tdx-host");
-- 
2.25.1