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This is a standalone version of VMware Balloon driver. Ballooning is a technique that allows hypervisor dynamically limit the amount of memory available to the guest (with guest cooperation). In the overcommit scenario, when hypervisor set detects that it needs to shuffle some memory, it instructs the driver to allocate certain number of pages, and the underlying memory gets returned to the hypervisor. Later hypervisor may return memory to the guest by reattaching memory to the pageframes and instructing the driver to "deflate" balloon. We are submitting a standalone driver because KVM maintainer (Avi Kivity) expressed opinion (rightly) that our transport does not fit well into virtqueue paradigm and thus it does not make much sense to integrate with virtio. There were also some concerns whether current ballooning technique is the right thing. If there appears a better framework to achieve this we are prepared to evaluate and switch to using it, but in the meantime we'd like to get this driver upstream. We want to get the driver accepted in distributions so that users do not have to deal with an out-of-tree module and many distributions have "upstream first" requirement. The driver has been shipping for a number of years and users running on VMware platform will have it installed as part of VMware Tools even if it will not come from a distribution, thus there should not be additional risk in pulling the driver into mainline. The driver will only activate if host is VMware so everyone else should not be affected at all. Signed-off-by: Dmitry Torokhov <dtor@vmware.com> Cc: Avi Kivity <avi@redhat.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
124 lines
3.8 KiB
C
124 lines
3.8 KiB
C
/*
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* VMware Detection 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/dmi.h>
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#include <linux/module.h>
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#include <asm/div64.h>
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#include <asm/vmware.h>
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#include <asm/x86_init.h>
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#define CPUID_VMWARE_INFO_LEAF 0x40000000
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#define VMWARE_HYPERVISOR_MAGIC 0x564D5868
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#define VMWARE_HYPERVISOR_PORT 0x5658
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#define VMWARE_PORT_CMD_GETVERSION 10
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#define VMWARE_PORT_CMD_GETHZ 45
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#define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \
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__asm__("inl (%%dx)" : \
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"=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \
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"0"(VMWARE_HYPERVISOR_MAGIC), \
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"1"(VMWARE_PORT_CMD_##cmd), \
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"2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \
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"memory");
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static inline int __vmware_platform(void)
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{
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uint32_t eax, ebx, ecx, edx;
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VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx);
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return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC;
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}
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static unsigned long vmware_get_tsc_khz(void)
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{
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uint64_t tsc_hz;
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uint32_t eax, ebx, ecx, edx;
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VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
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tsc_hz = eax | (((uint64_t)ebx) << 32);
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do_div(tsc_hz, 1000);
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BUG_ON(tsc_hz >> 32);
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printk(KERN_INFO "TSC freq read from hypervisor : %lu.%03lu MHz\n",
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(unsigned long) tsc_hz / 1000,
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(unsigned long) tsc_hz % 1000);
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return tsc_hz;
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}
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void __init vmware_platform_setup(void)
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{
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uint32_t eax, ebx, ecx, edx;
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VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
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if (ebx != UINT_MAX)
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x86_platform.calibrate_tsc = vmware_get_tsc_khz;
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else
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printk(KERN_WARNING
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"Failed to get TSC freq from the hypervisor\n");
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}
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/*
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* While checking the dmi string infomation, just checking the product
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* serial key should be enough, as this will always have a VMware
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* specific string when running under VMware hypervisor.
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*/
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int vmware_platform(void)
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{
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if (cpu_has_hypervisor) {
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unsigned int eax, ebx, ecx, edx;
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char hyper_vendor_id[13];
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cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &ebx, &ecx, &edx);
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memcpy(hyper_vendor_id + 0, &ebx, 4);
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memcpy(hyper_vendor_id + 4, &ecx, 4);
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memcpy(hyper_vendor_id + 8, &edx, 4);
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hyper_vendor_id[12] = '\0';
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if (!strcmp(hyper_vendor_id, "VMwareVMware"))
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return 1;
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} else if (dmi_available && dmi_name_in_serial("VMware") &&
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__vmware_platform())
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return 1;
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return 0;
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}
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EXPORT_SYMBOL(vmware_platform);
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/*
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* VMware hypervisor takes care of exporting a reliable TSC to the guest.
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* Still, due to timing difference when running on virtual cpus, the TSC can
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* be marked as unstable in some cases. For example, the TSC sync check at
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* bootup can fail due to a marginal offset between vcpus' TSCs (though the
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* TSCs do not drift from each other). Also, the ACPI PM timer clocksource
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* is not suitable as a watchdog when running on a hypervisor because the
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* kernel may miss a wrap of the counter if the vcpu is descheduled for a
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* long time. To skip these checks at runtime we set these capability bits,
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* so that the kernel could just trust the hypervisor with providing a
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* reliable virtual TSC that is suitable for timekeeping.
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*/
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void __cpuinit vmware_set_feature_bits(struct cpuinfo_x86 *c)
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{
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set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
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set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);
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}
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