From c9b5ad546e7d486465a3dd8c89245ac3707a4384 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Tue, 14 Jun 2016 12:56:01 +0200 Subject: 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: Martin Schwidefsky --- arch/s390/kernel/suspend.c | 24 +++++++++++++++++++----- arch/s390/kernel/vdso.c | 2 ++ 2 files changed, 21 insertions(+), 5 deletions(-) (limited to 'arch/s390/kernel') diff --git a/arch/s390/kernel/suspend.c b/arch/s390/kernel/suspend.c index 39e2f41b6cf0..c8ea715bfe10 100644 --- a/arch/s390/kernel/suspend.c +++ b/arch/s390/kernel/suspend.c @@ -98,10 +98,16 @@ int page_key_alloc(unsigned long pages) */ void page_key_read(unsigned long *pfn) { + struct page *page; unsigned long addr; - - addr = (unsigned long) page_address(pfn_to_page(*pfn)); - *(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr); + unsigned char key; + + 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; diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c index b89d19f6f2ab..eacda05b45d7 100644 --- a/arch/s390/kernel/vdso.c +++ b/arch/s390/kernel/vdso.c @@ -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; -- cgit