ANDROID: virt: gunyah: Add a gunyah hcall for ioremap

Add a gunyah hook for ioremap to let the hypervisor know what
iomem regions are being used by the guest.

Bug: 424772814
Change-Id: I46b25f704fcd2c35d16558718e36eef560f56bb9
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>

arch/arm64/gunyah/gunyah_hypercall.c

@@ -44,6 +44,7 @@ EXPORT_SYMBOL_GPL(arch_is_gunyah_guest);
 #define GUNYAH_HYPERCALL_MSGQ_RECV		GUNYAH_HYPERCALL(0x801C)
 #define GUNYAH_HYPERCALL_ADDRSPACE_MAP		GUNYAH_HYPERCALL(0x802B)
 #define GUNYAH_HYPERCALL_ADDRSPACE_UNMAP	GUNYAH_HYPERCALL(0x802C)
+#define GUNYAH_HYPERCALL_ADDRSPACE_CONFIG_VMMIO_RANGE	GUNYAH_HYPERCALL(0x8060)
 #define GUNYAH_HYPERCALL_MEMEXTENT_DONATE	GUNYAH_HYPERCALL(0x8061)
 #define GUNYAH_HYPERCALL_VCPU_RUN		GUNYAH_HYPERCALL(0x8065)
 #define GUNYAH_HYPERCALL_ADDRSPC_MODIFY_PAGES	GUNYAH_HYPERCALL(0x8069)
@@ -81,6 +82,34 @@ enum gunyah_error gunyah_hypercall_addrspc_modify_pages(u64 capid, u64 addr,
 }
 EXPORT_SYMBOL_GPL(gunyah_hypercall_addrspc_modify_pages);
 
+/**
+ * gunyah_hypercall_addrspc_configure_vmmio_range() - Configure virtual MMIO device regions for
+ *                                                    the address space.
+ * @capid: Address space capability ID
+ * @base: Base guest address of MMIO region
+ * @size: Size of the MMIO region
+ * @op: Map or Unmap
+ */
+enum gunyah_error gunyah_hypercall_addrspc_configure_vmmio_range(u64 capid, u64 base,
+						    u64 size, u64 op)
+{
+	struct arm_smccc_1_2_regs args = {
+		.a0 = GUNYAH_HYPERCALL_ADDRSPACE_CONFIG_VMMIO_RANGE,
+		.a1 = capid,
+		.a2 = base,
+		.a3 = size,
+		.a4 = op,
+		/* Reserved. Must be 0 */
+		.a5 = 0,
+	};
+	struct arm_smccc_1_2_regs res;
+
+	arm_smccc_1_2_hvc(&args, &res);
+
+	return res.a0;
+}
+EXPORT_SYMBOL_GPL(gunyah_hypercall_addrspc_configure_vmmio_range);
+
 /**
  * gunyah_hypercall_bell_send() - Assert a gunyah doorbell
  * @capid: capability ID of the doorbell

drivers/virt/coco/gunyah-guest/gunyah-guest.c

@@ -1,8 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0
-/* Copyright (c) 2025 Qualcomm Innovation Center, Inc. All rights reserved. */
+/* Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. */
 
 #include <linux/gunyah.h>
 #include <linux/init.h>
+#include <linux/io.h>
+#include <linux/pgtable.h>
 #include <linux/virtio_balloon.h>
 
 #include <asm/hypervisor.h>
@@ -16,6 +18,28 @@ struct addrspace_info_area_rootvm_addrspace_cap {
 
 static u64 our_addrspace_capid;
 
+static int gunyah_mmio_guard_ioremap_hook(phys_addr_t phys, size_t size, pgprot_t *prot)
+{
+	pteval_t protval = pgprot_val(*prot);
+	int ret;
+
+	/*
+	 * We only expect MMIO emulation for regions mapped with device
+	 * attributes.
+	 */
+	if (protval != PROT_DEVICE_nGnRE && protval != PROT_DEVICE_nGnRnE)
+		return 0;
+
+	ret = gunyah_hypercall_addrspc_configure_vmmio_range(our_addrspace_capid,
+				phys, size, GUNYAH_ADDRSPACE_VMMIO_CONFIGURE_OP_ADD_RANGE);
+
+	if (ret == GUNYAH_ERROR_UNIMPLEMENTED || ret == GUNYAH_ERROR_BUSY)
+		/* Gunyah would have configured VMMIO via DT */
+		ret = GUNYAH_ERROR_OK;
+
+	return gunyah_error_remap(ret);
+}
+
 #ifdef CONFIG_VIRTIO_BALLOON_HYP_OPS
 static void gunyah_page_relinquish(struct page *page,  unsigned int nr)
 {
@@ -71,6 +95,7 @@ static int __init gunyah_guest_init(void)
 
 	our_addrspace_capid = info->addrspace_cap;
 
+	arm64_ioremap_prot_hook_register(&gunyah_mmio_guard_ioremap_hook);
 #ifdef CONFIG_VIRTIO_BALLOON_HYP_OPS
 	virtio_balloon_hyp_ops = &gunyah_virtio_balloon_hyp_ops;
 #endif

include/linux/gunyah.h

@@ -600,8 +600,9 @@ gunyah_hypercall_vcpu_run(u64 capid, unsigned long *resume_data,
 #define GUNYAH_ADDRSPC_MODIFY_FLAG_SANITIZE_BIT		1
 enum gunyah_error
 gunyah_hypercall_addrspc_modify_pages(u64 capid, u64 addr, u64 size, u64 flags);
-
 enum gunyah_error
 gunyah_hypercall_addrspace_find_info_area(unsigned long *ipa, unsigned long *size);
-
+enum gunyah_error
+#define GUNYAH_ADDRSPACE_VMMIO_CONFIGURE_OP_ADD_RANGE	0
+gunyah_hypercall_addrspc_configure_vmmio_range(u64 capid, u64 base, u64 size, u64 op);
 #endif