Commit 605a140a authored by Ilias Stamatis's avatar Ilias Stamatis Committed by Paolo Bonzini
Browse files

math64.h: Add mul_s64_u64_shr() 



This function is needed for KVM's nested virtualization. The nested TSC
scaling implementation requires multiplying the signed TSC offset with
the unsigned TSC multiplier.

Signed-off-by: default avatarIlias Stamatis <ilstam@amazon.com>
Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210526184418.28881-2-ilstam@amazon.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent d501f747

include/linux/math64.h

+19 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#define _LINUX_MATH64_H



#include <linux/types.h>

#include <linux/math.h>

#include <vdso/math64.h>

#include <asm/div64.h>
@@ -234,6 +235,24 @@ static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift) 


#endif



#ifndef mul_s64_u64_shr

static inline u64 mul_s64_u64_shr(s64 a, u64 b, unsigned int shift)

{

	u64 ret;



	/*

	 * Extract the sign before the multiplication and put it back

	 * afterwards if needed.

	 */

	ret = mul_u64_u64_shr(abs(a), b, shift);



	if (a < 0)

		ret = -((s64) ret);



	return ret;

}

#endif /* mul_s64_u64_shr */



#ifndef mul_u64_u32_div

static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)

{