x86/mm: Manage CSV3 guest's private memory by CMA

hygon inclusion
category: feature
CVE: NA

---------------------------

The private memory of a CSV3 guest is isolated from VMM and has to be
physically contiguous. CMA (Contiguous Memory Allocator) is a memory
allocator within the kernel for contiguous physical memory.

Use the CMA for the CSV3 private memory management. In order to
support CSV3, select MMU and CMA when CONIFG_HYGON_CSV is
configured.

Signed-off-by: Xin Jiang <jiangxin@hygon.cn>
Signed-off-by: hanliyang <hanliyang@hygon.cn>

arch/x86/Kconfig

@@ -2020,6 +2020,8 @@ config HYGON_CSV
 	bool "Hygon secure virtualization CSV support"
 	default y
 	depends on CPU_SUP_HYGON && AMD_MEM_ENCRYPT
+	select MMU
+	select CMA
 	help
 	  Hygon CSV integrates secure processor, memory encryption and
 	  memory isolation to provide the ability to protect guest's private

arch/x86/include/asm/csv.h

@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Hygon China Secure Virtualization (CSV)
+ *
+ * Copyright (C) Hygon Info Technologies Ltd.
+ *
+ * Author: Jiang Xin <jiangxin@hygon.cn>
+ */
+
+#ifndef __ASM_X86_CSV_H__
+#define __ASM_X86_CSV_H__
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_HYGON_CSV
+
+struct csv_mem {
+	uint64_t start;
+	uint64_t size;
+};
+
+#define CSV_MR_ALIGN_BITS		(28)
+
+extern struct csv_mem *csv_smr;
+extern unsigned int csv_smr_num;
+
+void __init early_csv_reserve_mem(void);
+
+phys_addr_t csv_alloc_from_contiguous(size_t size, nodemask_t *nodes_allowed,
+				      unsigned int align);
+void csv_release_to_contiguous(phys_addr_t pa, size_t size);
+
+uint32_t csv_get_smr_entry_shift(void);
+
+#else	/* !CONFIG_HYGON_CSV */
+
+#define csv_smr		NULL
+#define csv_smr_num	0U
+
+static inline void __init early_csv_reserve_mem(void) { }
+
+static inline phys_addr_t
+csv_alloc_from_contiguous(size_t size, nodemask_t *nodes_allowed,
+			  unsigned int align) { return 0; }
+static inline void csv_release_to_contiguous(phys_addr_t pa, size_t size) { }
+
+static inline uint32_t csv_get_smr_entry_shift(void) { return 0; }
+
+#endif	/* CONFIG_HYGON_CSV */
+
+#endif	/* __ASSEMBLY__ */
+
+#endif	/* __ASM_X86_CSV_H__ */

arch/x86/kernel/setup.c

@@ -55,6 +55,7 @@
 #include <asm/unwind.h>
 #include <asm/vsyscall.h>
 #include <linux/vmalloc.h>
+#include <asm/csv.h>
 
 /*
  * max_low_pfn_mapped: highest directly mapped pfn < 4 GB
@@ -1219,6 +1220,10 @@ void __init setup_arch(char **cmdline_p)
 	early_acpi_boot_init();
 
 	initmem_init();
+
+	/* Try to reserve contiguous memory to support CSV3 */
+	early_csv_reserve_mem();
+
 	dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
 
 	if (boot_cpu_has(X86_FEATURE_GBPAGES))