From 4b9c9a11803eaa73b3223da9fcaea39b2f919d80 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 17 Jul 2015 06:51:23 +0200 Subject: [PATCH] xen: save linear p2m list address in shared info structure The virtual address of the linear p2m list should be stored in the shared info structure read by the Xen tools to be able to support 64 bit pv-domains larger than 512 GB. Additionally the linear p2m list interface includes a generation count which is changed prior to and after each mapping change of the p2m list. Reading the generation count the Xen tools can detect changes of the mappings and re-read the p2m list eventually. Signed-off-by: Juergen Gross Reviewed-by: David Vrabel Acked-by: Konrad Rzeszutek Wilk Signed-off-by: David Vrabel --- arch/x86/xen/p2m.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 8b7f18e200aa..b89983e9656f 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -263,6 +263,10 @@ void xen_setup_mfn_list_list(void) HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = virt_to_mfn(p2m_top_mfn); HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn; + HYPERVISOR_shared_info->arch.p2m_generation = 0; + HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr; + HYPERVISOR_shared_info->arch.p2m_cr3 = + xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir)); } /* Set up p2m_top to point to the domain-builder provided p2m pages */ @@ -478,8 +482,12 @@ static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) ptechk = lookup_address(vaddr, &level); if (ptechk == pte_pg) { + HYPERVISOR_shared_info->arch.p2m_generation++; + wmb(); /* Tools are synchronizing via p2m_generation. */ set_pmd(pmdp, __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE)); + wmb(); /* Tools are synchronizing via p2m_generation. */ + HYPERVISOR_shared_info->arch.p2m_generation++; pte_newpg[i] = NULL; } @@ -577,8 +585,12 @@ static bool alloc_p2m(unsigned long pfn) spin_lock_irqsave(&p2m_update_lock, flags); if (pte_pfn(*ptep) == p2m_pfn) { + HYPERVISOR_shared_info->arch.p2m_generation++; + wmb(); /* Tools are synchronizing via p2m_generation. */ set_pte(ptep, pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL)); + wmb(); /* Tools are synchronizing via p2m_generation. */ + HYPERVISOR_shared_info->arch.p2m_generation++; if (mid_mfn) mid_mfn[mididx] = virt_to_mfn(p2m); p2m = NULL; @@ -630,6 +642,11 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) return true; } + /* + * The interface requires atomic updates on p2m elements. + * xen_safe_write_ulong() is using __put_user which does an atomic + * store via asm(). + */ if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn))) return true; -- 2.20.1