From f10cd522c5fbfec9ae3cc01967868c9c2401ed23 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Tue, 6 Sep 2011 17:41:47 +0100 Subject: xen: disable PV spinlocks on HVM PV spinlocks cannot possibly work with the current code because they are enabled after pvops patching has already been done, and because PV spinlocks use a different data structure than native spinlocks so we cannot switch between them dynamically. A spinlock that has been taken once by the native code (__ticket_spin_lock) cannot be taken by __xen_spin_lock even after it has been released. Reported-and-Tested-by: Stefan Bader Signed-off-by: Stefano Stabellini Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/smp.c | 1 - 1 file changed, 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index d4fc6d454f8..041d4fe9dfe 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -532,7 +532,6 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus) WARN_ON(xen_smp_intr_init(0)); xen_init_lock_cpu(0); - xen_init_spinlocks(); } static int __cpuinit xen_hvm_cpu_up(unsigned int cpu) -- cgit v1.2.3-70-g09d2 From e3b73c4a25e9a5705b4ef28b91676caf01f9bc9f Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Tue, 13 Sep 2011 10:17:32 -0400 Subject: xen/e820: if there is no dom0_mem=, don't tweak extra_pages. The patch "xen: use maximum reservation to limit amount of usable RAM" (d312ae878b6aed3912e1acaaf5d0b2a9d08a4f11) breaks machines that do not use 'dom0_mem=' argument with: reserve RAM buffer: 000000133f2e2000 - 000000133fffffff (XEN) mm.c:4976:d0 Global bit is set to kernel page fffff8117e (XEN) domain_crash_sync called from entry.S (XEN) Domain 0 (vcpu#0) crashed on cpu#0: ... The reason being that the last E820 entry is created using the 'extra_pages' (which is based on how many pages have been freed). The mentioned git commit sets the initial value of 'extra_pages' using a hypercall which returns the number of pages (if dom0_mem has been used) or -1 otherwise. If the later we return with MAX_DOMAIN_PAGES as basis for calculation: return min(max_pages, MAX_DOMAIN_PAGES); and use it: extra_limit = xen_get_max_pages(); if (extra_limit >= max_pfn) extra_pages = extra_limit - max_pfn; else extra_pages = 0; which means we end up with extra_pages = 128GB in PFNs (33554432) - 8GB in PFNs (2097152, on this specific box, can be larger or smaller), and then we add that value to the E820 making it: Xen: 00000000ff000000 - 0000000100000000 (reserved) Xen: 0000000100000000 - 000000133f2e2000 (usable) which is clearly wrong. It should look as so: Xen: 00000000ff000000 - 0000000100000000 (reserved) Xen: 0000000100000000 - 000000027fbda000 (usable) Naturally this problem does not present itself if dom0_mem=max:X is used. CC: stable@kernel.org Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/setup.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'arch') diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index ff3dfa17681..09688eb4a89 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -305,10 +305,12 @@ char * __init xen_memory_setup(void) sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); extra_limit = xen_get_max_pages(); - if (extra_limit >= max_pfn) - extra_pages = extra_limit - max_pfn; - else - extra_pages = 0; + if (max_pfn + extra_pages > extra_limit) { + if (extra_limit > max_pfn) + extra_pages = extra_limit - max_pfn; + else + extra_pages = 0; + } extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820); -- cgit v1.2.3-70-g09d2 From 61cca2fab7ecba18f9b9680cd736ef5fa82ad3b1 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Thu, 15 Sep 2011 08:52:40 +0100 Subject: xen/i386: follow-up to "replace order-based range checking of M2P table by linear one" The numbers obtained from the hypervisor really can't ever lead to an overflow here, only the original calculation going through the order of the range could have. This avoids the (as Jeremy points outs) somewhat ugly NULL-based calculation here. Signed-off-by: Jan Beulich Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/mmu.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'arch') diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 24abc1f50dc..a3872f7632e 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -1721,10 +1721,8 @@ void __init xen_setup_machphys_mapping(void) machine_to_phys_nr = MACH2PHYS_NR_ENTRIES; } #ifdef CONFIG_X86_32 - if ((machine_to_phys_mapping + machine_to_phys_nr) - < machine_to_phys_mapping) - machine_to_phys_nr = (unsigned long *)NULL - - machine_to_phys_mapping; + WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1)) + < machine_to_phys_mapping); #endif } -- cgit v1.2.3-70-g09d2