Commit c3a7a61c authored by Lianbo Jiang's avatar Lianbo Jiang Committed by Borislav Petkov
Browse files

x86/ioremap: Add an ioremap_encrypted() helper 



When SME is enabled, the memory is encrypted in the first kernel. In
this case, SME also needs to be enabled in the kdump kernel, and we have
to remap the old memory with the memory encryption mask.

The case of concern here is if SME is active in the first kernel,
and it is active too in the kdump kernel. There are four cases to be
considered:

a. dump vmcore
   It is encrypted in the first kernel, and needs be read out in the
   kdump kernel.

b. crash notes
   When dumping vmcore, the people usually need to read useful
   information from notes, and the notes is also encrypted.

c. iommu device table
   It's encrypted in the first kernel, kdump kernel needs to access its
   content to analyze and get information it needs.

d. mmio of AMD iommu
   not encrypted in both kernels

Add a new bool parameter @encrypted to __ioremap_caller(). If set,
memory will be remapped with the SME mask.

Add a new function ioremap_encrypted() to explicitly pass in a true
value for @encrypted. Use ioremap_encrypted() for the above a, b, c
cases.

 [ bp: cleanup commit message, extern defs in io.h and drop forgotten
   include. ]

Signed-off-by: default avatarLianbo Jiang <lijiang@redhat.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Cc: kexec@lists.infradead.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: akpm@linux-foundation.org
Cc: dan.j.williams@intel.com
Cc: bhelgaas@google.com
Cc: baiyaowei@cmss.chinamobile.com
Cc: tiwai@suse.de
Cc: brijesh.singh@amd.com
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Cc: jroedel@suse.de
Link: https://lkml.kernel.org/r/20180927071954.29615-2-lijiang@redhat.com
parent b3541fbc

arch/x86/include/asm/io.h

+2 −1
Original line number Diff line number Diff line
@@ -187,11 +187,12 @@ extern void __iomem *ioremap_nocache(resource_size_t offset, unsigned long size) 
#define ioremap_nocache ioremap_nocache

extern void __iomem *ioremap_uc(resource_size_t offset, unsigned long size);

#define ioremap_uc ioremap_uc



extern void __iomem *ioremap_cache(resource_size_t offset, unsigned long size);

#define ioremap_cache ioremap_cache

extern void __iomem *ioremap_prot(resource_size_t offset, unsigned long size, unsigned long prot_val);

#define ioremap_prot ioremap_prot

extern void __iomem *ioremap_encrypted(resource_size_t phys_addr, unsigned long size);

#define ioremap_encrypted ioremap_encrypted



/**

 * ioremap     -   map bus memory into CPU space

arch/x86/mm/ioremap.c

+16 −8
Original line number Diff line number Diff line
@@ -131,7 +131,8 @@ static void __ioremap_check_mem(resource_size_t addr, unsigned long size, 
 * caller shouldn't need to know that small detail.

 */

static void __iomem *__ioremap_caller(resource_size_t phys_addr,

		unsigned long size, enum page_cache_mode pcm, void *caller)

		unsigned long size, enum page_cache_mode pcm,

		void *caller, bool encrypted)

{

	unsigned long offset, vaddr;

	resource_size_t last_addr;
@@ -199,7 +200,7 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, 
	 * resulting mapping.

	 */

	prot = PAGE_KERNEL_IO;

	if (sev_active() && mem_flags.desc_other)

	if ((sev_active() && mem_flags.desc_other) || encrypted)

		prot = pgprot_encrypted(prot);



	switch (pcm) {
@@ -291,7 +292,7 @@ void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size) 
	enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC_MINUS;



	return __ioremap_caller(phys_addr, size, pcm,

				__builtin_return_address(0));

				__builtin_return_address(0), false);

}

EXPORT_SYMBOL(ioremap_nocache);
@@ -324,7 +325,7 @@ void __iomem *ioremap_uc(resource_size_t phys_addr, unsigned long size) 
	enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC;



	return __ioremap_caller(phys_addr, size, pcm,

				__builtin_return_address(0));

				__builtin_return_address(0), false);

}

EXPORT_SYMBOL_GPL(ioremap_uc);
@@ -341,7 +342,7 @@ EXPORT_SYMBOL_GPL(ioremap_uc); 
void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size)

{

	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WC,

					__builtin_return_address(0));

					__builtin_return_address(0), false);

}

EXPORT_SYMBOL(ioremap_wc);
@@ -358,14 +359,21 @@ EXPORT_SYMBOL(ioremap_wc); 
void __iomem *ioremap_wt(resource_size_t phys_addr, unsigned long size)

{

	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WT,

					__builtin_return_address(0));

					__builtin_return_address(0), false);

}

EXPORT_SYMBOL(ioremap_wt);



void __iomem *ioremap_encrypted(resource_size_t phys_addr, unsigned long size)

{

	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WB,

				__builtin_return_address(0), true);

}

EXPORT_SYMBOL(ioremap_encrypted);



void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size)

{

	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WB,

				__builtin_return_address(0));

				__builtin_return_address(0), false);

}

EXPORT_SYMBOL(ioremap_cache);
@@ -374,7 +382,7 @@ void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size, 
{

	return __ioremap_caller(phys_addr, size,

				pgprot2cachemode(__pgprot(prot_val)),

				__builtin_return_address(0));

				__builtin_return_address(0), false);

}

EXPORT_SYMBOL(ioremap_prot);

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