From 7f9140626c757b773624b97865cb53c2a8348a69 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Thu, 26 Jul 2012 12:47:40 -0400 Subject: xen/mmu: Copy and revector the P2M tree. Please first read the description in "xen/p2m: Add logic to revector a P2M tree to use __va leafs" patch. The 'xen_revector_p2m_tree()' function allocates a new P2M tree copies the contents of the old one in it, and returns the new one. At this stage, the __ka address space (which is what the old P2M tree was using) is partially disassembled. The cleanup_highmap has removed the PMD entries from 0-16MB and anything past _brk_end up to the max_pfn_mapped (which is the end of the ramdisk). We have revectored the P2M tree (and the one for save/restore as well) to use new shiny __va address to new MFNs. The xen_start_info has been taken care of already in 'xen_setup_kernel_pagetable()' and xen_start_info->shared_info in 'xen_setup_shared_info()', so we are free to roam and delete PMD entries - which is exactly what we are going to do. We rip out the __ka for the old P2M array. [v1: Fix smatch warnings] [v2: memset was doing 0 instead of 0xff] Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/mmu.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) (limited to 'arch/x86/xen/mmu.c') diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index b44e6a88ea74..a640949f78d4 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -1183,9 +1183,64 @@ static __init void xen_mapping_pagetable_reserve(u64 start, u64 end) static void xen_post_allocator_init(void); +#ifdef CONFIG_X86_64 +static void __init xen_cleanhighmap(unsigned long vaddr, + unsigned long vaddr_end) +{ + unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1; + pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr); + + /* NOTE: The loop is more greedy than the cleanup_highmap variant. + * We include the PMD passed in on _both_ boundaries. */ + for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PAGE_SIZE)); + pmd++, vaddr += PMD_SIZE) { + if (pmd_none(*pmd)) + continue; + if (vaddr < (unsigned long) _text || vaddr > kernel_end) + set_pmd(pmd, __pmd(0)); + } + /* In case we did something silly, we should crash in this function + * instead of somewhere later and be confusing. */ + xen_mc_flush(); +} +#endif static void __init xen_pagetable_setup_done(pgd_t *base) { +#ifdef CONFIG_X86_64 + unsigned long size; + unsigned long addr; +#endif + xen_setup_shared_info(); +#ifdef CONFIG_X86_64 + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + unsigned long new_mfn_list; + + size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); + + /* On 32-bit, we get zero so this never gets executed. */ + new_mfn_list = xen_revector_p2m_tree(); + if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) { + /* using __ka address and sticking INVALID_P2M_ENTRY! */ + memset((void *)xen_start_info->mfn_list, 0xff, size); + + /* We should be in __ka space. */ + BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map); + addr = xen_start_info->mfn_list; + size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); + /* We roundup to the PMD, which means that if anybody at this stage is + * using the __ka address of xen_start_info or xen_start_info->shared_info + * they are in going to crash. Fortunatly we have already revectored + * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */ + size = roundup(size, PMD_SIZE); + xen_cleanhighmap(addr, addr + size); + + memblock_free(__pa(xen_start_info->mfn_list), size); + /* And revector! Bye bye old array */ + xen_start_info->mfn_list = new_mfn_list; + } + } +#endif xen_post_allocator_init(); } @@ -1824,6 +1879,8 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) /* Our (by three pages) smaller Xen pagetable that we are using */ memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE); + /* Revector the xen_start_info */ + xen_start_info = (struct start_info *)__va(__pa(xen_start_info)); } #else /* !CONFIG_X86_64 */ static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD); -- cgit v1.2.3