From: Vitaly Kuznetsov Date: Thu, 30 Jun 2016 15:56:37 +0000 (+0200) Subject: xen: introduce xen_vcpu_id mapping X-Git-Tag: v4.1.12-92~55^2~12 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=3b42f4a8aee6fb24d9851bda2c3514d9f9f43e0d;p=users%2Fjedix%2Flinux-maple.git xen: introduce xen_vcpu_id mapping It may happen that Xen's and Linux's ideas of vCPU id diverge. In particular, when we crash on a secondary vCPU we may want to do kdump and unlike plain kexec where we do migrate_to_reboot_cpu() we try booting on the vCPU which crashed. This doesn't work very well for PVHVM guests as we have a number of hypercalls where we pass vCPU id as a parameter. These hypercalls either fail or do something unexpected. To solve the issue introduce percpu xen_vcpu_id mapping. ARM and PV guests get direct mapping for now. Boot CPU for PVHVM guest gets its id from CPUID. With secondary CPUs it is a bit more trickier. Currently, we initialize IPI vectors before these CPUs boot so we can't use CPUID. Use ACPI ids from MADT instead. Signed-off-by: Vitaly Kuznetsov Signed-off-by: David Vrabel (cherry picked from commit 88e957d6e47f1232ad15b21e54a44f1147ea8c1b) Signed-off-by: Bob Liu Orabug: 24820937 Conflicts: arch/arm/xen/enlighten.c --- diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index 27d42e80c3a10..a19260266c27d 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -41,6 +41,10 @@ struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info; DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); static struct vcpu_info __percpu *xen_vcpu_info; +/* Linux <-> Xen vCPU id mapping */ +DEFINE_PER_CPU(int, xen_vcpu_id) = -1; +EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); + /* These are unused until we support booting "pre-ballooned" */ unsigned long xen_released_pages; struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; @@ -161,6 +165,9 @@ static void xen_percpu_init(void) pr_info("Xen: initializing cpu%d\n", cpu); vcpup = per_cpu_ptr(xen_vcpu_info, cpu); + /* Direct vCPU id mapping for ARM guests. */ + per_cpu(xen_vcpu_id, cpu) = cpu; + info.mfn = virt_to_gfn(vcpup); info.offset = xen_offset_in_page(vcpup); @@ -308,7 +315,13 @@ static int __init xen_guest_init(void) if (xen_vcpu_info == NULL) return -ENOMEM; - if (gnttab_setup_auto_xlat_frames(grant_frames)) { + /* Direct vCPU id mapping for ARM guests. */ + per_cpu(xen_vcpu_id, 0) = 0; + + xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames(); + if (xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn, + &xen_auto_xlat_grant_frames.vaddr, + xen_auto_xlat_grant_frames.count)) { free_percpu(xen_vcpu_info); return -ENOMEM; } diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 3853741c4d163..d8e05dc7ecddf 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -58,6 +58,7 @@ #include #include #include +#include #include #include #include @@ -118,6 +119,10 @@ DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); */ DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); +/* Linux <-> Xen vCPU id mapping */ +DEFINE_PER_CPU(int, xen_vcpu_id) = -1; +EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); + enum xen_domain_type xen_domain_type = XEN_NATIVE; EXPORT_SYMBOL_GPL(xen_domain_type); @@ -1147,8 +1152,11 @@ void xen_setup_vcpu_info_placement(void) { int cpu; - for_each_possible_cpu(cpu) + for_each_possible_cpu(cpu) { + /* Set up direct vCPU id mapping for PV guests. */ + per_cpu(xen_vcpu_id, cpu) = cpu; xen_vcpu_setup(cpu); + } /* xen_vcpu_setup managed to place the vcpu_info within the * percpu area for all cpus, so make use of it. Note that for @@ -1753,6 +1761,9 @@ asmlinkage __visible void __init xen_start_kernel(void) #endif xen_raw_console_write("about to get started...\n"); + /* Let's presume PV guests always boot on vCPU with id 0. */ + per_cpu(xen_vcpu_id, 0) = 0; + xen_setup_runstate_info(0); xen_efi_init(); @@ -1821,6 +1832,12 @@ static void __init init_hvm_pv_info(void) xen_setup_features(); + cpuid(base + 4, &eax, &ebx, &ecx, &edx); + if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT) + this_cpu_write(xen_vcpu_id, ebx); + else + this_cpu_write(xen_vcpu_id, smp_processor_id()); + pv_info.name = "Xen HVM"; xen_domain_type = XEN_HVM_DOMAIN; @@ -1832,6 +1849,10 @@ static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action, int cpu = (long)hcpu; switch (action) { case CPU_UP_PREPARE: + if (cpu_acpi_id(cpu) != U32_MAX) + per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu); + else + per_cpu(xen_vcpu_id, cpu) = cpu; xen_vcpu_setup(cpu); if (xen_have_vector_callback) { if (xen_feature(XENFEAT_hvm_safe_pvclock)) diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h index 355275bad2cff..c9c532d566237 100644 --- a/include/xen/xen-ops.h +++ b/include/xen/xen-ops.h @@ -9,6 +9,12 @@ DECLARE_PER_CPU(struct vcpu_info *, xen_vcpu); +DECLARE_PER_CPU(int, xen_vcpu_id); +static inline int xen_vcpu_nr(int cpu) +{ + return per_cpu(xen_vcpu_id, cpu); +} + void xen_arch_pre_suspend(void); void xen_arch_post_suspend(int suspend_cancelled);