Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 606b21d4 authored by Tom Lendacky's avatar Tom Lendacky Committed by Thomas Gleixner
Browse files

x86/io: Unroll string I/O when SEV is active 



Secure Encrypted Virtualization (SEV) does not support string I/O, so
unroll the string I/O operation into a loop operating on one element at
a time.

[ tglx: Gave the static key a real name instead of the obscure __sev ]

Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Tested-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: kvm@vger.kernel.org
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20171020143059.3291-14-brijesh.singh@amd.com
parent 1958b5fc

arch/x86/include/asm/io.h

+39 −4
Original line number Original line Diff line number Diff line
@@ -266,6 +266,21 @@ static inline void slow_down_io(void) 




#endif

#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)						\

#define BUILDIO(bwl, bw, type)						\

static inline void out##bwl(unsigned type value, int port)		\

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) \

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				\

		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)	\

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				\

		asm volatile("rep; ins" #bwl				\

		     : "+D"(addr), "+c"(count) : "d"(port) : "memory");	\

			     : "+D"(addr), "+c"(count)			\

			     : "d"(port) : "memory");			\

	}								\

}

}





BUILDIO(b, b, char)

BUILDIO(b, b, char)

arch/x86/mm/mem_encrypt.c

+8 −0
Original line number Original line Diff line number Diff line
@@ -41,6 +41,8 @@ static char sme_cmdline_off[] __initdata = "off"; 
 */

 */

u64 sme_me_mask __section(.data) = 0;

u64 sme_me_mask __section(.data) = 0;

EXPORT_SYMBOL_GPL(sme_me_mask);

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);

static bool sev_enabled __section(.data);
@@ -313,6 +315,12 @@ void __init mem_encrypt_init(void) 
	if (sev_active())

	if (sev_active())

		dma_ops = &sev_dma_ops;

		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",

	pr_info("AMD %s active\n",

		sev_active() ? "Secure Encrypted Virtualization (SEV)"

		sev_active() ? "Secure Encrypted Virtualization (SEV)"

			     : "Secure Memory Encryption (SME)");

			     : "Secure Memory Encryption (SME)");