Subject: [PATCH V2 03/14] x86/set_memory: Add x86_set_memory_enc static call support

From: Tianyu Lan <[email-masked]>
Date: Wed, 4 Aug 2021 14:44:59 -0400

From: Tianyu Lan <[email-masked]>

Hyper-V and other platforms(e.g Intel and AMD) want to override
the __set_memory_enc_dec(). Add x86_set_memory_enc static
call here and platforms can hook their implementation.

Signed-off-by: Tianyu Lan <[email-masked]>
---
 arch/x86/include/asm/set_memory.h | 4 ++++
 arch/x86/mm/pat/set_memory.c      | 9 +++++++++
 2 files changed, 13 insertions(+)

diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index 43fa081a1adb..490f2cfc00fa 100644
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -4,6 +4,7 @@
 
 #include <asm/page.h>
 #include <asm-generic/set_memory.h>
+#include <linux/static_call.h>
 
 /*
  * The set_memory_* API can be used to change various attributes of a virtual
@@ -84,6 +85,9 @@ int set_direct_map_invalid_noflush(struct page *page);
 int set_direct_map_default_noflush(struct page *page);
 bool kernel_page_present(struct page *page);
 
+int dummy_set_memory_enc(unsigned long addr, int numpages, bool enc);
+DECLARE_STATIC_CALL(x86_set_memory_enc, dummy_set_memory_enc);
+
 extern int kernel_set_to_readonly;
 
 #ifdef CONFIG_X86_64
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index ad8a5c586a35..68e9ab522cea 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -18,6 +18,7 @@
 #include <linux/libnvdimm.h>
 #include <linux/vmstat.h>
 #include <linux/kernel.h>
+#include <linux/static_call.h>
 
 #include <asm/e820/api.h>
 #include <asm/processor.h>
@@ -66,6 +67,9 @@ static const int cpa_warn_level = CPA_PROTECT;
  */
 static DEFINE_SPINLOCK(cpa_lock);
 
+static int default_set_memory_enc(unsigned long addr, int numpages, bool enc);
+DEFINE_STATIC_CALL(x86_set_memory_enc, default_set_memory_enc);
+
 #define CPA_FLUSHTLB 1
 #define CPA_ARRAY 2
 #define CPA_PAGES_ARRAY 4
@@ -1981,6 +1985,11 @@ int set_memory_global(unsigned long addr, int numpages)
 }
 
 static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
+{
+	return static_call(x86_set_memory_enc)(addr, numpages, enc);
+}
+
+static int default_set_memory_enc(unsigned long addr, int numpages, bool enc)
 {
 	struct cpa_data cpa;
 	int ret;
-- 
2.25.1