[PATCH V2 4/4] x86: correctly detect hypervisor
Konrad Rzeszutek Wilk
konrad.wilk at oracle.com
Mon Aug 5 14:34:26 UTC 2013
On Mon, Aug 05, 2013 at 11:38:14AM +0800, Jason Wang wrote:
> On 07/25/2013 04:54 PM, Jason Wang wrote:
> > We try to handle the hypervisor compatibility mode by detecting hypervisor
> > through a specific order. This is not robust, since hypervisors may implement
> > each others features.
> >
> > This patch tries to handle this situation by always choosing the last one in the
> > CPUID leaves. This is done by letting .detect() returns a priority instead of
> > true/false and just re-using the CPUID leaf where the signature were found as
> > the priority (or 1 if it was found by DMI). Then we can just pick hypervisor who
> > has the highest priority. Other sophisticated detection method could also be
> > implemented on top.
> >
> > Suggested by H. Peter Anvin and Paolo Bonzini.
> >
> > Cc: Thomas Gleixner <tglx at linutronix.de>
> > Cc: Ingo Molnar <mingo at redhat.com>
> > Cc: H. Peter Anvin <hpa at zytor.com>
> > Cc: x86 at kernel.org
> > Cc: K. Y. Srinivasan <kys at microsoft.com>
> > Cc: Haiyang Zhang <haiyangz at microsoft.com>
> > Cc: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
> > Cc: Jeremy Fitzhardinge <jeremy at goop.org>
> > Cc: Doug Covelli <dcovelli at vmware.com>
> > Cc: Borislav Petkov <bp at suse.de>
> > Cc: Dan Hecht <dhecht at vmware.com>
> > Cc: Paul Gortmaker <paul.gortmaker at windriver.com>
> > Cc: Marcelo Tosatti <mtosatti at redhat.com>
> > Cc: Gleb Natapov <gleb at redhat.com>
> > Cc: Paolo Bonzini <pbonzini at redhat.com>
> > Cc: Frederic Weisbecker <fweisbec at gmail.com>
> > Cc: linux-kernel at vger.kernel.org
> > Cc: devel at linuxdriverproject.org
> > Cc: kvm at vger.kernel.org
> > Cc: xen-devel at lists.xensource.com
> > Cc: virtualization at lists.linux-foundation.org
> > Signed-off-by: Jason Wang <jasowang at redhat.com>
> > ---
>
> Ping, any comments and acks for this series?
Could you provide me with a git branch so I can test it overnight please?
>
> Thanks
> > arch/x86/include/asm/hypervisor.h | 2 +-
> > arch/x86/kernel/cpu/hypervisor.c | 15 +++++++--------
> > arch/x86/kernel/cpu/mshyperv.c | 13 ++++++++-----
> > arch/x86/kernel/cpu/vmware.c | 8 ++++----
> > arch/x86/kernel/kvm.c | 6 ++----
> > arch/x86/xen/enlighten.c | 9 +++------
> > 6 files changed, 25 insertions(+), 28 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
> > index 2d4b5e6..e42f758 100644
> > --- a/arch/x86/include/asm/hypervisor.h
> > +++ b/arch/x86/include/asm/hypervisor.h
> > @@ -33,7 +33,7 @@ struct hypervisor_x86 {
> > const char *name;
> >
> > /* Detection routine */
> > - bool (*detect)(void);
> > + uint32_t (*detect)(void);
> >
> > /* Adjust CPU feature bits (run once per CPU) */
> > void (*set_cpu_features)(struct cpuinfo_x86 *);
> > diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
> > index 8727921..36ce402 100644
> > --- a/arch/x86/kernel/cpu/hypervisor.c
> > +++ b/arch/x86/kernel/cpu/hypervisor.c
> > @@ -25,11 +25,6 @@
> > #include <asm/processor.h>
> > #include <asm/hypervisor.h>
> >
> > -/*
> > - * Hypervisor detect order. This is specified explicitly here because
> > - * some hypervisors might implement compatibility modes for other
> > - * hypervisors and therefore need to be detected in specific sequence.
> > - */
> > static const __initconst struct hypervisor_x86 * const hypervisors[] =
> > {
> > #ifdef CONFIG_XEN_PVHVM
> > @@ -49,15 +44,19 @@ static inline void __init
> > detect_hypervisor_vendor(void)
> > {
> > const struct hypervisor_x86 *h, * const *p;
> > + uint32_t pri, max_pri = 0;
> >
> > for (p = hypervisors; p < hypervisors + ARRAY_SIZE(hypervisors); p++) {
> > h = *p;
> > - if (h->detect()) {
> > + pri = h->detect();
> > + if (pri != 0 && pri > max_pri) {
> > + max_pri = pri;
> > x86_hyper = h;
> > - printk(KERN_INFO "Hypervisor detected: %s\n", h->name);
> > - break;
> > }
> > }
> > +
> > + if (max_pri)
> > + printk(KERN_INFO "Hypervisor detected: %s\n", x86_hyper->name);
> > }
> >
> > void init_hypervisor(struct cpuinfo_x86 *c)
> > diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> > index 8f4be53..71a39f3 100644
> > --- a/arch/x86/kernel/cpu/mshyperv.c
> > +++ b/arch/x86/kernel/cpu/mshyperv.c
> > @@ -27,20 +27,23 @@
> > struct ms_hyperv_info ms_hyperv;
> > EXPORT_SYMBOL_GPL(ms_hyperv);
> >
> > -static bool __init ms_hyperv_platform(void)
> > +static uint32_t __init ms_hyperv_platform(void)
> > {
> > u32 eax;
> > u32 hyp_signature[3];
> >
> > if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
> > - return false;
> > + return 0;
> >
> > cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
> > &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
> >
> > - return eax >= HYPERV_CPUID_MIN &&
> > - eax <= HYPERV_CPUID_MAX &&
> > - !memcmp("Microsoft Hv", hyp_signature, 12);
> > + if (eax >= HYPERV_CPUID_MIN &&
> > + eax <= HYPERV_CPUID_MAX &&
> > + !memcmp("Microsoft Hv", hyp_signature, 12))
> > + return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
> > +
> > + return 0;
> > }
> >
> > static cycle_t read_hv_clock(struct clocksource *arg)
> > diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
> > index 7076878..628a059 100644
> > --- a/arch/x86/kernel/cpu/vmware.c
> > +++ b/arch/x86/kernel/cpu/vmware.c
> > @@ -93,7 +93,7 @@ static void __init vmware_platform_setup(void)
> > * serial key should be enough, as this will always have a VMware
> > * specific string when running under VMware hypervisor.
> > */
> > -static bool __init vmware_platform(void)
> > +static uint32_t __init vmware_platform(void)
> > {
> > if (cpu_has_hypervisor) {
> > unsigned int eax;
> > @@ -102,12 +102,12 @@ static bool __init vmware_platform(void)
> > cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
> > &hyper_vendor_id[1], &hyper_vendor_id[2]);
> > if (!memcmp(hyper_vendor_id, "VMwareVMware", 12))
> > - return true;
> > + return CPUID_VMWARE_INFO_LEAF;
> > } else if (dmi_available && dmi_name_in_serial("VMware") &&
> > __vmware_platform())
> > - return true;
> > + return 1;
> >
> > - return false;
> > + return 0;
> > }
> >
> > /*
> > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> > index a96d32c..7817afd 100644
> > --- a/arch/x86/kernel/kvm.c
> > +++ b/arch/x86/kernel/kvm.c
> > @@ -498,11 +498,9 @@ void __init kvm_guest_init(void)
> > #endif
> > }
> >
> > -static bool __init kvm_detect(void)
> > +static uint32_t __init kvm_detect(void)
> > {
> > - if (!kvm_para_available())
> > - return false;
> > - return true;
> > + return kvm_cpuid_base();
> > }
> >
> > const struct hypervisor_x86 x86_hyper_kvm __refconst = {
> > diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> > index 193097e..2fcaedc 100644
> > --- a/arch/x86/xen/enlighten.c
> > +++ b/arch/x86/xen/enlighten.c
> > @@ -1720,15 +1720,12 @@ static void __init xen_hvm_guest_init(void)
> > xen_hvm_init_mmu_ops();
> > }
> >
> > -static bool __init xen_hvm_platform(void)
> > +static uint32_t __init xen_hvm_platform(void)
> > {
> > if (xen_pv_domain())
> > - return false;
> > -
> > - if (!xen_cpuid_base())
> > - return false;
> > + return 0;
> >
> > - return true;
> > + return xen_cpuid_base();
> > }
> >
> > bool xen_hvm_need_lapic(void)
>
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