diff --git a/arch/x86/virt/vmx/tdx/seamldr.c b/arch/x86/virt/vmx/tdx/seamldr.c
index b2b6a439d417..bcb1386380ef 100644
--- a/arch/x86/virt/vmx/tdx/seamldr.c
+++ b/arch/x86/virt/vmx/tdx/seamldr.c
@@ -7,6 +7,8 @@
 #define pr_fmt(fmt)	"seamldr: " fmt
 
 #include <linux/bug.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
 #include <linux/spinlock.h>
 
 #include <asm/cpufeature.h>
@@ -18,6 +20,35 @@
 /* P-SEAMLDR SEAMCALL leaf function */
 #define P_SEAMLDR_INFO			0x8000000000000000
 
+#define SEAMLDR_MAX_NR_MODULE_PAGES	496
+#define SEAMLDR_MAX_NR_SIG_PAGES	1
+
+/*
+ * The seamldr_params "scenario" field specifies the operation mode:
+ * 0: Install TDX module from scratch (not used by kernel)
+ * 1: Update existing TDX module to a compatible version
+ */
+#define SEAMLDR_SCENARIO_UPDATE		1
+
+/*
+ * This is the "SEAMLDR_PARAMS" data structure defined in the
+ * "SEAM Loader (SEAMLDR) Interface Specification".
+ *
+ * It is the in-memory ABI that the kernel passes to the P-SEAMLDR
+ * to update the TDX module. It breaks the TDX module image up in
+ * page-size pieces.
+ */
+struct seamldr_params {
+	u32	version;
+	u32	scenario;
+	u64	sigstruct_pages_pa_list[SEAMLDR_MAX_NR_SIG_PAGES];
+	u8	reserved[104];
+	u64	module_nr_pages;
+	u64	module_pages_pa_list[SEAMLDR_MAX_NR_MODULE_PAGES];
+} __packed;
+
+static_assert(sizeof(struct seamldr_params) == 4096);
+
 /*
  * Serialize P-SEAMLDR calls since the hardware only allows a single CPU to
  * interact with P-SEAMLDR simultaneously. Use raw version as the calls can
@@ -55,6 +86,106 @@ int seamldr_get_info(struct seamldr_info *seamldr_info)
 }
 EXPORT_SYMBOL_FOR_MODULES(seamldr_get_info, "tdx-host");
 
+#define TDX_IMAGE_VERSION_2		0x200
+
+/* First page of the on-disk module update image: */
+struct tdx_image_header {
+	u16	version;
+	u16	checksum;
+	u8	signature[8];
+	u32	sigstruct_nr_pages;
+	u32	module_nr_pages;
+	u8	reserved[4076];
+} __packed;
+
+#define TDX_IMAGE_HEADER_SIZE sizeof(struct tdx_image_header)
+static_assert(TDX_IMAGE_HEADER_SIZE == 4096);
+
+/*
+ * Intel TDX module update ABI structure. aka. "TDX module blob".
+ * This is the on-disk format that fw_upload lands in a kernel
+ * buffer.
+ *
+ * @payload contains sigstruct pages followed by module pages.
+ */
+struct tdx_image {
+	struct tdx_image_header header;
+	u8 payload[];
+};
+
+/*
+ * Given a vmalloc() allocation, write all of the backing physical
+ * addresses to pa_list[]. Caller guarantees that the array is big
+ * enough.
+ */
+static void populate_pa_list(u64 *pa_list, const u8 *vmalloc_addr, u32 vmalloc_len_pages)
+{
+	int i;
+
+	for (i = 0; i < vmalloc_len_pages; i++) {
+		unsigned long offset = i * PAGE_SIZE;
+		unsigned long pfn = vmalloc_to_pfn(&vmalloc_addr[offset]);
+
+		pa_list[i] = pfn << PAGE_SHIFT;
+	}
+}
+
+static void populate_seamldr_params(struct seamldr_params *params,
+				    const u8 *sig, u32 sig_nr_pages,
+				    const u8 *mod, u32 mod_nr_pages)
+{
+	params->version		= 0;
+	params->scenario	= SEAMLDR_SCENARIO_UPDATE;
+	params->module_nr_pages	= mod_nr_pages;
+
+	populate_pa_list(params->sigstruct_pages_pa_list, sig, sig_nr_pages);
+	populate_pa_list(params->module_pages_pa_list,	  mod, mod_nr_pages);
+}
+
+/*
+ * @image points to a vmalloc()'d 'struct tdx_image'. Transform
+ * it into @params which is the P-SEAMLDR ABI format.
+ */
+static int init_seamldr_params(struct seamldr_params *params,
+			       const struct tdx_image *image,
+			       u32 image_len)
+{
+	const struct tdx_image_header *header	= &image->header;
+
+	u32 sigstruct_len	= header->sigstruct_nr_pages * PAGE_SIZE;
+	u32 module_len		= header->module_nr_pages    * PAGE_SIZE;
+
+	u8 *header_start	= (u8 *)header;
+	u8 *header_end		= header_start + TDX_IMAGE_HEADER_SIZE;
+
+	u8 *sigstruct_start	= header_end;
+	u8 *sigstruct_end	= sigstruct_start + sigstruct_len;
+
+	u8 *module_start	= sigstruct_end;
+
+	/* Check the calculated payload size against the image size. */
+	if (TDX_IMAGE_HEADER_SIZE + sigstruct_len + module_len != image_len)
+		return -EINVAL;
+
+	/* Reject unsupported tdx_image ABI versions. */
+	if (header->version != TDX_IMAGE_VERSION_2)
+		return -EINVAL;
+
+	if (header->sigstruct_nr_pages > SEAMLDR_MAX_NR_SIG_PAGES ||
+	    header->module_nr_pages    > SEAMLDR_MAX_NR_MODULE_PAGES)
+		return -EINVAL;
+
+	if (memcmp(header->signature, "TDX-BLOB", sizeof(header->signature)))
+		return -EINVAL;
+
+	if (memchr_inv(header->reserved, 0, sizeof(header->reserved)))
+		return -EINVAL;
+
+	populate_seamldr_params(params, sigstruct_start, header->sigstruct_nr_pages,
+					module_start,    header->module_nr_pages);
+	return 0;
+}
+
 /**
  * seamldr_install_module - Install a new TDX module.
  * @data: Pointer to the TDX module image.
@@ -64,7 +195,31 @@ EXPORT_SYMBOL_FOR_MODULES(seamldr_get_info, "tdx-host");
  */
 int seamldr_install_module(const u8 *data, u32 data_len)
 {
+	struct seamldr_params *params;
+	const struct tdx_image *image;
+	int ret;
+
+	/*
+	 * init_seamldr_params() reads the header early.
+	 * Ensure there is enough data to do at least that.
+	 */
+	if (data_len < TDX_IMAGE_HEADER_SIZE)
+		return -EINVAL;
+
+	image = (const struct tdx_image *)data;
+
+	params = kzalloc_obj(*params);
+	if (!params)
+		return -ENOMEM;
+
+	/* Populate 'params' from 'image'. */
+	ret = init_seamldr_params(params, image, data_len);
+	if (ret)
+		goto out;
+
 	/* TODO: Update TDX module here */
-	return 0;
+out:
+	kfree(params);
+	return ret;
 }
 EXPORT_SYMBOL_FOR_MODULES(seamldr_install_module, "tdx-host");