x86/io: Unroll string I/O when SEV is active (606b21d4) · Commits · 戴 / test

arch/x86/include/asm/io.h

+39 −4

Original line number	Diff line number	Diff line
		@@ -266,6 +266,21 @@ static inline void slow_down_io(void)

		#endif

		#ifdef CONFIG_AMD_MEM_ENCRYPT
		#include <linux/jump_label.h>

		extern struct static_key_false sev_enable_key;
		static inline bool sev_key_active(void)
		{
		return static_branch_unlikely(&sev_enable_key);
		}

		#else /* !CONFIG_AMD_MEM_ENCRYPT */

		static inline bool sev_key_active(void) { return false; }

		#endif /* CONFIG_AMD_MEM_ENCRYPT */

		#define BUILDIO(bwl, bw, type) \
		static inline void out##bwl(unsigned type value, int port) \
		{ \
		@@ -296,14 +311,34 @@ static inline unsigned type in##bwl##_p(int port) \
		\
		static inline void outs##bwl(int port, const void *addr, unsigned long count) \
		{ \
		if (sev_key_active()) { \
		unsigned type value = (unsigned type )addr; \
		while (count) { \
		out##bwl(*value, port); \
		value++; \
		count--; \
		} \
		} else { \
		asm volatile("rep; outs" #bwl \
		: "+S"(addr), "+c"(count) : "d"(port) : "memory"); \
		: "+S"(addr), "+c"(count) \
		: "d"(port) : "memory"); \
		} \
		} \
		\
		static inline void ins##bwl(int port, void *addr, unsigned long count) \
		{ \
		if (sev_key_active()) { \
		unsigned type value = (unsigned type )addr; \
		while (count) { \
		*value = in##bwl(port); \
		value++; \
		count--; \
		} \
		} else { \
		asm volatile("rep; ins" #bwl \
		: "+D"(addr), "+c"(count) : "d"(port) : "memory"); \
		: "+D"(addr), "+c"(count) \
		: "d"(port) : "memory"); \
		} \
		}

		BUILDIO(b, b, char)

+8 −0

Original line number	Diff line number	Diff line
		@@ -41,6 +41,8 @@ static char sme_cmdline_off[] __initdata = "off";
		*/
		u64 sme_me_mask __section(.data) = 0;
		EXPORT_SYMBOL_GPL(sme_me_mask);
		DEFINE_STATIC_KEY_FALSE(sev_enable_key);
		EXPORT_SYMBOL_GPL(sev_enable_key);

		static bool sev_enabled __section(.data);

		@@ -313,6 +315,12 @@ void __init mem_encrypt_init(void)
		if (sev_active())
		dma_ops = &sev_dma_ops;

		/*
		* With SEV, we need to unroll the rep string I/O instructions.
		*/
		if (sev_active())
		static_branch_enable(&sev_enable_key);

		pr_info("AMD %s active\n",
		sev_active() ? "Secure Encrypted Virtualization (SEV)"
		: "Secure Memory Encryption (SME)");