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Commit c9b5ad54 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

s390/mm: tag normal pages vs pages used in page tables 



The ESSA instruction has a new option that allows to tag pages that
are not used as a page table. Without the tag the hypervisor has to
assume that any guest page could be used in a page table inside the
guest. This forces the hypervisor to flush all guest TLB entries
whenever a host page table entry is invalidated. With the tag
the host can skip the TLB flush if the page is tagged as normal page.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 520eccdf

arch/s390/include/asm/page-states.h

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#define ESSA_SET_POT_VOLATILE		4

#define ESSA_SET_STABLE_RESIDENT	5

#define ESSA_SET_STABLE_IF_RESIDENT	6

#define ESSA_SET_STABLE_NODAT		7



#define ESSA_MAX	ESSA_SET_STABLE_IF_RESIDENT

arch/s390/include/asm/page.h

+3 −0
Original line number Diff line number Diff line
@@ -133,6 +133,9 @@ static inline int page_reset_referenced(unsigned long addr) 
struct page;

void arch_free_page(struct page *page, int order);

void arch_alloc_page(struct page *page, int order);

void arch_set_page_dat(struct page *page, int order);

void arch_set_page_nodat(struct page *page, int order);

int arch_test_page_nodat(struct page *page);

void arch_set_page_states(int make_stable);



static inline int devmem_is_allowed(unsigned long pfn)

arch/s390/include/asm/setup.h

+2 −1
Original line number Diff line number Diff line
@@ -106,7 +106,8 @@ extern void pfault_fini(void); 


void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault);



extern void cmma_init(void);

void cmma_init(void);

void cmma_init_nodat(void);



extern void (*_machine_restart)(char *command);

extern void (*_machine_halt)(void);

arch/s390/kernel/suspend.c

+19 −5
Original line number Diff line number Diff line
@@ -98,10 +98,16 @@ int page_key_alloc(unsigned long pages) 
 */

void page_key_read(unsigned long *pfn)

{

	struct page *page;

	unsigned long addr;

	unsigned char key;



	addr = (unsigned long) page_address(pfn_to_page(*pfn));

	*(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);

	page = pfn_to_page(*pfn);

	addr = (unsigned long) page_address(page);

	key = (unsigned char) page_get_storage_key(addr) & 0x7f;

	if (arch_test_page_nodat(page))

		key |= 0x80;

	*(unsigned char *) pfn = key;

}



/*
@@ -126,8 +132,16 @@ void page_key_memorize(unsigned long *pfn) 
 */

void page_key_write(void *address)

{

	page_set_storage_key((unsigned long) address,

			     page_key_rp->data[page_key_rx], 0);

	struct page *page;

	unsigned char key;



	key = page_key_rp->data[page_key_rx];

	page_set_storage_key((unsigned long) address, key & 0x7f, 0);

	page = virt_to_page(address);

	if (key & 0x80)

		arch_set_page_nodat(page, 0);

	else

		arch_set_page_dat(page, 0);

	if (++page_key_rx >= PAGE_KEY_DATA_SIZE)

		return;

	page_key_rp = page_key_rp->next;

arch/s390/kernel/vdso.c

+2 −0
Original line number Diff line number Diff line
@@ -157,6 +157,8 @@ int vdso_alloc_per_cpu(struct lowcore *lowcore) 
	page_frame = get_zeroed_page(GFP_KERNEL);

	if (!segment_table || !page_table || !page_frame)

		goto out;

	arch_set_page_dat(virt_to_page(segment_table), SEGMENT_ORDER);

	arch_set_page_dat(virt_to_page(page_table), 0);



	/* Initialize per-cpu vdso data page */

	vd = (struct vdso_per_cpu_data *) page_frame;