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tools headers: Import iosubmit_cmds512()

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Import iosubmit_cmds512() from arch/x86/include/asm/io.h into tools/ so
it can be used by VFIO selftests to interact with Intel DSA devices.

Also pull in movdir64b() from arch/x86/include/asm/special_insns.h into
tools/, which is the underlying instruction used by iosubmit_cmds512().

Changes made when importing: None

Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20250822212518.4156428-21-dmatlack@google.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
David Matlack
2025-08-22 21:25:07 +00:00
committed by Alex Williamson
parent 2223587df5
commit 3fe305773b
2 changed files with 53 additions and 0 deletions
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26
tools/arch/x86/include/asm/io.h
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@@ -4,6 +4,7 @@
#include <linux/compiler.h>
#include <linux/types.h>
#include "special_insns.h"
#define build_mmio_read(name, size, type, reg, barrier) \
static inline type name(const volatile void __iomem *addr) \
@@ -72,4 +73,29 @@ build_mmio_write(__writeq, "q", u64, "r", )
#include <asm-generic/io.h>
/**
* iosubmit_cmds512 - copy data to single MMIO location, in 512-bit units
* @dst: destination, in MMIO space (must be 512-bit aligned)
* @src: source
* @count: number of 512 bits quantities to submit
*
* Submit data from kernel space to MMIO space, in units of 512 bits at a
* time. Order of access is not guaranteed, nor is a memory barrier
* performed afterwards.
*
* Warning: Do not use this helper unless your driver has checked that the CPU
* instruction is supported on the platform.
*/
static inline void iosubmit_cmds512(void __iomem *dst, const void *src,
size_t count)
{
const u8 *from = src;
const u8 *end = from + count * 64;
while (from < end) {
movdir64b(dst, from);
from += 64;
}
}
#endif /* _TOOLS_ASM_X86_IO_H */

27
tools/arch/x86/include/asm/special_insns.h Normal file
View File

@@ -0,0 +1,27 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _TOOLS_ASM_X86_SPECIAL_INSNS_H
#define _TOOLS_ASM_X86_SPECIAL_INSNS_H
/* The dst parameter must be 64-bytes aligned */
static inline void movdir64b(void *dst, const void *src)
{
const struct { char _[64]; } *__src = src;
struct { char _[64]; } *__dst = dst;
/*
* MOVDIR64B %(rdx), rax.
*
* Both __src and __dst must be memory constraints in order to tell the
* compiler that no other memory accesses should be reordered around
* this one.
*
* Also, both must be supplied as lvalues because this tells
* the compiler what the object is (its size) the instruction accesses.
* I.e., not the pointers but what they point to, thus the deref'ing '*'.
*/
asm volatile(".byte 0x66, 0x0f, 0x38, 0xf8, 0x02"
: "+m" (*__dst)
: "m" (*__src), "a" (__dst), "d" (__src));
}
#endif /* _TOOLS_ASM_X86_SPECIAL_INSNS_H */