From 4aedc102c3a31f590f8d3894d2b1fdf01f9585f3 Mon Sep 17 00:00:00 2001
From: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Date: Mon, 5 Feb 2024 11:50:47 -0800
Subject: [PATCH] ANDROID: arm64: virt: Make the page_relinquish call generic

Move out the kvm specific page_relinquish call and introduce a generic
hypervisor_ops structure. Based on the hypervisor running underneath the
guest, populate the operations to make specific hypercalls.

Bug: 315173520
Change-Id: I93d5a92553a04d56811b0666dec6eacc1ca168e7
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
---
 arch/arm64/include/asm/hypervisor.h | 11 ++++++++
 arch/arm64/kernel/setup.c           |  1 +
 arch/arm64/mm/mem_relinquish.c      | 40 +++++++++++++++++------------
 3 files changed, 35 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/include/asm/hypervisor.h b/arch/arm64/include/asm/hypervisor.h
index 9b4e4ed79623..9ad85b15dab0 100644
--- a/arch/arm64/include/asm/hypervisor.h
+++ b/arch/arm64/include/asm/hypervisor.h
@@ -2,6 +2,9 @@
 #ifndef _ASM_ARM64_HYPERVISOR_H
 #define _ASM_ARM64_HYPERVISOR_H
 
+#include <linux/memory.h>
+#include <linux/mm.h>
+
 #include <asm/xen/hypervisor.h>
 
 void kvm_init_hyp_services(void);
@@ -10,6 +13,14 @@ void kvm_arm_init_hyp_services(void);
 void kvm_init_memshare_services(void);
 void kvm_init_ioremap_services(void);
 
+struct hypervisor_ops {
+#ifdef CONFIG_MEMORY_RELINQUISH
+	void (*page_relinquish)(struct page *page);
+#endif
+};
+
+extern struct hypervisor_ops hyp_ops;
+
 #ifdef CONFIG_MEMORY_RELINQUISH
 void kvm_init_memrelinquish_services(void);
 #else
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index a0bc75b721e0..20ca892d5e5c 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -58,6 +58,7 @@
 
 static int num_standard_resources;
 static struct resource *standard_resources;
+struct hypervisor_ops hyp_ops;
 
 phys_addr_t __fdt_pointer __initdata;
 
diff --git a/arch/arm64/mm/mem_relinquish.c b/arch/arm64/mm/mem_relinquish.c
index 7948098288e3..08bf966c7fc5 100644
--- a/arch/arm64/mm/mem_relinquish.c
+++ b/arch/arm64/mm/mem_relinquish.c
@@ -14,6 +14,24 @@
 
 static unsigned long memshare_granule_sz;
 
+static void kvm_page_relinquish(struct page *page)
+{
+	phys_addr_t phys, end;
+	u32 func_id = ARM_SMCCC_VENDOR_HYP_KVM_MEM_RELINQUISH_FUNC_ID;
+
+	phys = page_to_phys(page);
+	end = phys + PAGE_SIZE;
+
+	while (phys < end) {
+		struct arm_smccc_res res;
+
+		arm_smccc_1_1_invoke(func_id, phys, 0, 0, &res);
+		BUG_ON(res.a0 != SMCCC_RET_SUCCESS);
+
+		phys += memshare_granule_sz;
+	}
+}
+
 void kvm_init_memrelinquish_services(void)
 {
 	int i;
@@ -34,6 +52,9 @@ void kvm_init_memrelinquish_services(void)
 		return;
 
 	memshare_granule_sz = res.a0;
+
+	if (memshare_granule_sz)
+		hyp_ops.page_relinquish = kvm_page_relinquish;
 }
 
 bool kvm_has_memrelinquish_services(void)
@@ -44,22 +65,7 @@ EXPORT_SYMBOL_GPL(kvm_has_memrelinquish_services);
 
 void page_relinquish(struct page *page)
 {
-	phys_addr_t phys, end;
-	u32 func_id = ARM_SMCCC_VENDOR_HYP_KVM_MEM_RELINQUISH_FUNC_ID;
-
-	if (!memshare_granule_sz)
-		return;
-
-	phys = page_to_phys(page);
-	end = phys + PAGE_SIZE;
-
-	while (phys < end) {
-		struct arm_smccc_res res;
-
-		arm_smccc_1_1_invoke(func_id, phys, 0, 0, &res);
-		BUG_ON(res.a0 != SMCCC_RET_SUCCESS);
-
-		phys += memshare_granule_sz;
-	}
+	if (hyp_ops.page_relinquish)
+		hyp_ops.page_relinquish(page);
 }
 EXPORT_SYMBOL_GPL(page_relinquish);