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Commit 64e1f0c5 authored by Halil Pasic's avatar Halil Pasic Committed by Heiko Carstens
Browse files

s390/mm: force swiotlb for protected virtualization 



On s390, protected virtualization guests have to use bounced I/O
buffers.  That requires some plumbing.

Let us make sure, any device that uses DMA API with direct ops correctly
is spared from the problems, that a hypervisor attempting I/O to a
non-shared page would bring.

Signed-off-by: default avatarHalil Pasic <pasic@linux.ibm.com>
Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: default avatarMichael Mueller <mimu@linux.ibm.com>
Tested-by: default avatarMichael Mueller <mimu@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
parent 45488c48

arch/s390/Kconfig

+4 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0

config ARCH_HAS_MEM_ENCRYPT

        def_bool y



config MMU

	def_bool y
@@ -186,6 +189,7 @@ config S390 
	select VIRT_CPU_ACCOUNTING

	select ARCH_HAS_SCALED_CPUTIME

	select HAVE_NMI

	select SWIOTLB





config SCHED_OMIT_FRAME_POINTER

arch/s390/include/asm/mem_encrypt.h

0 → 100644
+17 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef S390_MEM_ENCRYPT_H__

#define S390_MEM_ENCRYPT_H__



#ifndef __ASSEMBLY__



#define sme_me_mask	0ULL



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

extern bool sev_active(void);



int set_memory_encrypted(unsigned long addr, int numpages);

int set_memory_decrypted(unsigned long addr, int numpages);



#endif	/* __ASSEMBLY__ */



#endif	/* S390_MEM_ENCRYPT_H__ */

arch/s390/mm/init.c

+47 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/mman.h>

#include <linux/mm.h>

#include <linux/swap.h>

#include <linux/swiotlb.h>

#include <linux/smp.h>

#include <linux/init.h>

#include <linux/pagemap.h>
@@ -29,6 +30,7 @@ 
#include <linux/export.h>

#include <linux/cma.h>

#include <linux/gfp.h>

#include <linux/dma-mapping.h>

#include <asm/processor.h>

#include <linux/uaccess.h>

#include <asm/pgtable.h>
@@ -42,6 +44,8 @@ 
#include <asm/sclp.h>

#include <asm/set_memory.h>

#include <asm/kasan.h>

#include <asm/dma-mapping.h>

#include <asm/uv.h>



pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir);
@@ -128,6 +132,47 @@ void mark_rodata_ro(void) 
	pr_info("Write protected read-only-after-init data: %luk\n", size >> 10);

}



int set_memory_encrypted(unsigned long addr, int numpages)

{

	int i;



	/* make specified pages unshared, (swiotlb, dma_free) */

	for (i = 0; i < numpages; ++i) {

		uv_remove_shared(addr);

		addr += PAGE_SIZE;

	}

	return 0;

}



int set_memory_decrypted(unsigned long addr, int numpages)

{

	int i;

	/* make specified pages shared (swiotlb, dma_alloca) */

	for (i = 0; i < numpages; ++i) {

		uv_set_shared(addr);

		addr += PAGE_SIZE;

	}

	return 0;

}



/* are we a protected virtualization guest? */

bool sev_active(void)

{

	return is_prot_virt_guest();

}



/* protected virtualization */

static void pv_init(void)

{

	if (!is_prot_virt_guest())

		return;



	/* make sure bounce buffers are shared */

	swiotlb_init(1);

	swiotlb_update_mem_attributes();

	swiotlb_force = SWIOTLB_FORCE;

}



void __init mem_init(void)

{

	cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
@@ -136,6 +181,8 @@ void __init mem_init(void) 
	set_max_mapnr(max_low_pfn);

        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);



	pv_init();



	/* Setup guest page hinting */

	cmma_init();