diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst
index c42580e..af7bc2c 100644
--- a/Documentation/virt/kvm/arm/hypercalls.rst
+++ b/Documentation/virt/kvm/arm/hypercalls.rst
@@ -116,3 +116,29 @@
 |                     |          |    +---------------------------------------------+
 |                     |          |    | ``INVALID_PARAMETER (-3)``                  |
 +---------------------+----------+----+---------------------------------------------+
+
+``ARM_SMCCC_KVM_FUNC_MMIO_GUARD``
+----------------------------------
+
+Request that a given memory region is handled as MMIO by the hypervisor,
+allowing accesses to this region to be emulated by the KVM host. The size of the
+region is equal to the memory protection granule advertised by
+``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO``.
+
++---------------------+-------------------------------------------------------------+
+| Presence:           | Optional; pKVM protected guests only.                       |
++---------------------+-------------------------------------------------------------+
+| Calling convention: | HVC64                                                       |
++---------------------+----------+--------------------------------------------------+
+| Function ID:        | (uint32) | 0xC6000007                                       |
++---------------------+----------+----+---------------------------------------------+
+| Arguments:          | (uint64) | R1 | Base IPA of MMIO memory region              |
+|                     +----------+----+---------------------------------------------+
+|                     | (uint64) | R2 | Reserved / Must be zero                     |
+|                     +----------+----+---------------------------------------------+
+|                     | (uint64) | R3 | Reserved / Must be zero                     |
++---------------------+----------+----+---------------------------------------------+
+| Return Values:      | (int64)  | R0 | ``SUCCESS (0)``                             |
+|                     |          |    +---------------------------------------------+
+|                     |          |    | ``INVALID_PARAMETER (-3)``                  |
++---------------------+----------+----+---------------------------------------------+
diff --git a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
index 8256cf6..56a3859 100644
--- a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
+++ b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
@@ -9,8 +9,10 @@
 
 #include <linux/arm-smccc.h>
 #include <linux/array_size.h>
+#include <linux/io.h>
 #include <linux/mem_encrypt.h>
 #include <linux/mm.h>
+#include <linux/pgtable.h>
 
 #include <asm/hypervisor.h>
 
@@ -67,6 +69,36 @@
 	.decrypt	= pkvm_set_memory_decrypted,
 };
 
+static int mmio_guard_ioremap_hook(phys_addr_t phys, size_t size,
+				   pgprot_t *prot)
+{
+	phys_addr_t end;
+	pteval_t protval = pgprot_val(*prot);
+
+	/*
+	 * We only expect MMIO emulation for regions mapped with device
+	 * attributes.
+	 */
+	if (protval != PROT_DEVICE_nGnRE && protval != PROT_DEVICE_nGnRnE)
+		return 0;
+
+	phys = PAGE_ALIGN_DOWN(phys);
+	end = phys + PAGE_ALIGN(size);
+
+	while (phys < end) {
+		const int func_id = ARM_SMCCC_VENDOR_HYP_KVM_MMIO_GUARD_FUNC_ID;
+		int err;
+
+		err = arm_smccc_do_one_page(func_id, phys);
+		if (err)
+			return err;
+
+		phys += PAGE_SIZE;
+	}
+
+	return 0;
+}
+
 void pkvm_init_hyp_services(void)
 {
 	int i;
@@ -89,4 +121,7 @@
 
 	pkvm_granule = res.a0;
 	arm64_mem_crypt_ops_register(&pkvm_crypt_ops);
+
+	if (kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_MMIO_GUARD))
+		arm64_ioremap_prot_hook_register(&mmio_guard_ioremap_hook);
 }
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 9cb7c95..e93c1f7 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -118,6 +118,7 @@
 #define ARM_SMCCC_KVM_FUNC_HYP_MEMINFO		2
 #define ARM_SMCCC_KVM_FUNC_MEM_SHARE		3
 #define ARM_SMCCC_KVM_FUNC_MEM_UNSHARE		4
+#define ARM_SMCCC_KVM_FUNC_MMIO_GUARD		7
 #define ARM_SMCCC_KVM_FUNC_FEATURES_2		127
 #define ARM_SMCCC_KVM_NUM_FUNCS			128
 
@@ -158,6 +159,12 @@
 			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
 			   ARM_SMCCC_KVM_FUNC_MEM_UNSHARE)
 
+#define ARM_SMCCC_VENDOR_HYP_KVM_MMIO_GUARD_FUNC_ID			\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_64,				\
+			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
+			   ARM_SMCCC_KVM_FUNC_MMIO_GUARD)
+
 /* ptp_kvm counter type ID */
 #define KVM_PTP_VIRT_COUNTER			0
 #define KVM_PTP_PHYS_COUNTER			1