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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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a71dbdaa8c
Commit 61f01dd941 ("x86_64, asm: Work around AMD SYSRET SS descriptor
attribute issue") makes AMD processors set SS to __KERNEL_DS in
__switch_to() to deal with cases when SS is NULL.
This breaks Xen PV guests who do not want to load SS with__KERNEL_DS.
Since the problem that the commit is trying to address would have to be
fixed in the hypervisor (if it in fact exists under Xen) there is no
reason to set X86_BUG_SYSRET_SS_ATTRS flag for PV VPCUs here.
This can be easily achieved by adding x86_hyper_xen_hvm.set_cpu_features
op which will clear this flag. (And since this structure is no longer
HVM-specific we should do some renaming).
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
88 lines
2.1 KiB
C
88 lines
2.1 KiB
C
/*
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* Common hypervisor code
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*
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* Copyright (C) 2008, VMware, Inc.
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* Author : Alok N Kataria <akataria@vmware.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <linux/module.h>
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#include <asm/processor.h>
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#include <asm/hypervisor.h>
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static const __initconst struct hypervisor_x86 * const hypervisors[] =
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{
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#ifdef CONFIG_XEN
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&x86_hyper_xen,
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#endif
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&x86_hyper_vmware,
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&x86_hyper_ms_hyperv,
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#ifdef CONFIG_KVM_GUEST
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&x86_hyper_kvm,
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#endif
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};
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const struct hypervisor_x86 *x86_hyper;
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EXPORT_SYMBOL(x86_hyper);
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static inline void __init
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detect_hypervisor_vendor(void)
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{
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const struct hypervisor_x86 *h, * const *p;
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uint32_t pri, max_pri = 0;
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for (p = hypervisors; p < hypervisors + ARRAY_SIZE(hypervisors); p++) {
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h = *p;
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pri = h->detect();
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if (pri != 0 && pri > max_pri) {
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max_pri = pri;
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x86_hyper = h;
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}
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}
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if (max_pri)
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printk(KERN_INFO "Hypervisor detected: %s\n", x86_hyper->name);
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}
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void init_hypervisor(struct cpuinfo_x86 *c)
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{
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if (x86_hyper && x86_hyper->set_cpu_features)
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x86_hyper->set_cpu_features(c);
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}
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void __init init_hypervisor_platform(void)
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{
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detect_hypervisor_vendor();
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if (!x86_hyper)
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return;
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init_hypervisor(&boot_cpu_data);
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if (x86_hyper->init_platform)
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x86_hyper->init_platform();
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}
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bool __init hypervisor_x2apic_available(void)
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{
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return x86_hyper &&
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x86_hyper->x2apic_available &&
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x86_hyper->x2apic_available();
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}
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