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Commit 23758461 authored by Janosch Frank's avatar Janosch Frank
Browse files

Merge tag 'hlp_stage1' of... 

Merge tag 'hlp_stage1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvms390/next

KVM: s390: initial host large page support

- must be enabled via module parameter hpage=1
- cannot be used together with nested
- does support migration
- does support hugetlbfs
- no THP yet
parents 57cb198c a4499382

Documentation/virtual/kvm/api.txt

+16 −0
Original line number Diff line number Diff line
@@ -4391,6 +4391,22 @@ all such vmexits. 


Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits.



7.14 KVM_CAP_S390_HPAGE_1M



Architectures: s390

Parameters: none

Returns: 0 on success, -EINVAL if hpage module parameter was not set

	 or cmma is enabled



With this capability the KVM support for memory backing with 1m pages

through hugetlbfs can be enabled for a VM. After the capability is

enabled, cmma can't be enabled anymore and pfmfi and the storage key

interpretation are disabled. If cmma has already been enabled or the

hpage module parameter is not set to 1, -EINVAL is returned.



While it is generally possible to create a huge page backed VM without

this capability, the VM will not be able to run.



8. Other capabilities.

----------------------

arch/s390/include/asm/gmap.h

+10 −0
Original line number Diff line number Diff line
@@ -9,6 +9,14 @@ 
#ifndef _ASM_S390_GMAP_H

#define _ASM_S390_GMAP_H



/* Generic bits for GMAP notification on DAT table entry changes. */

#define GMAP_NOTIFY_SHADOW	0x2

#define GMAP_NOTIFY_MPROT	0x1



/* Status bits only for huge segment entries */

#define _SEGMENT_ENTRY_GMAP_IN		0x8000	/* invalidation notify bit */

#define _SEGMENT_ENTRY_GMAP_UC		0x4000	/* dirty (migration) */



/**

 * struct gmap_struct - guest address space

 * @list: list head for the mm->context gmap list
@@ -132,4 +140,6 @@ void gmap_pte_notify(struct mm_struct *, unsigned long addr, pte_t *, 
int gmap_mprotect_notify(struct gmap *, unsigned long start,

			 unsigned long len, int prot);



void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long dirty_bitmap[4],

			     unsigned long gaddr, unsigned long vmaddr);

#endif /* _ASM_S390_GMAP_H */

arch/s390/include/asm/hugetlb.h

+4 −1
Original line number Diff line number Diff line
@@ -37,7 +37,10 @@ static inline int prepare_hugepage_range(struct file *file, 
	return 0;

}



#define arch_clear_hugepage_flags(page)		do { } while (0)

static inline void arch_clear_hugepage_flags(struct page *page)

{

	clear_bit(PG_arch_1, &page->flags);

}



static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr,

				  pte_t *ptep, unsigned long sz)

arch/s390/include/asm/mmu.h

+2 −0
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ typedef struct { 
	unsigned int uses_skeys:1;

	/* The mmu context uses CMM. */

	unsigned int uses_cmm:1;

	/* The gmaps associated with this context are allowed to use huge pages. */

	unsigned int allow_gmap_hpage_1m:1;

} mm_context_t;



#define INIT_MM_CONTEXT(name)						   \

arch/s390/include/asm/mmu_context.h

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ static inline int init_new_context(struct task_struct *tsk, 
	mm->context.has_pgste = 0;

	mm->context.uses_skeys = 0;

	mm->context.uses_cmm = 0;

	mm->context.allow_gmap_hpage_1m = 0;

#endif

	switch (mm->context.asce_limit) {

	case _REGION2_SIZE: