linux-stable.git/arch/x86/kernel/cpu/hypervisor.c, branch linux-4.3.y

hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests

2015-05-05T17:27:43+00:00

Commit 61f01dd941ba ("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 
Reported-by: Sander Eikelenboom 
Signed-off-by: David Vrabel

x86: Correctly detect hypervisor

2013-08-05T13:35:33+00:00

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() return 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.

Acked-by: K. Y. Srinivasan 
Cc: Haiyang Zhang 
Cc: Konrad Rzeszutek Wilk 
Cc: Jeremy Fitzhardinge 
Cc: Doug Covelli 
Cc: Borislav Petkov 
Cc: Dan Hecht 
Cc: Paul Gortmaker 
Cc: Marcelo Tosatti 
Cc: Gleb Natapov 
Cc: Paolo Bonzini 
Cc: Frederic Weisbecker 
Signed-off-by: Jason Wang 
Link: http://lkml.kernel.org/r/1374742475-2485-4-git-send-email-jasowang@redhat.com
Signed-off-by: H. Peter Anvin

x86: delete __cpuinit usage from all x86 files

2013-07-14T23:36:56+00:00

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit  -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings.  In any case, they are temporary and harmless.

This removes all the arch/x86 uses of the __cpuinit macros from
all C files.  x86 only had the one __CPUINIT used in assembly files,
and it wasn't paired off with a .previous or a __FINIT, so we can
delete it directly w/o any corresponding additional change there.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: x86@kernel.org
Acked-by: Ingo Molnar 
Acked-by: Thomas Gleixner 
Acked-by: H. Peter Anvin 
Signed-off-by: Paul Gortmaker

x86/apic: Allow x2apic without IR on VMware platform

2013-01-24T12:11:18+00:00

This patch updates x2apic initializaition code to allow x2apic
on VMware platform even without interrupt remapping support.
The hypervisor_x2apic_available hook was added in x2apic
initialization code and used by KVM and XEN, before this.
I have also cleaned up that code to export this hook through the
hypervisor_x86 structure.

Compile tested for KVM and XEN configs, this patch doesn't have
any functional effect on those two platforms.

On VMware platform, verified that x2apic is used in physical
mode on products that support this.

Signed-off-by: Alok N Kataria 
Reviewed-by: Doug Covelli 
Reviewed-by: Dan Hecht 
Acked-by: H. Peter Anvin 
Cc: Konrad Rzeszutek Wilk 
Cc: Jeremy Fitzhardinge 
Cc: Avi Kivity 
Link: http://lkml.kernel.org/r/1358466282.423.60.camel@akataria-dtop.eng.vmware.com
Signed-off-by: Ingo Molnar

x86, hyper: fix build with !CONFIG_KVM_GUEST

2012-07-18T20:01:48+00:00

Signed-off-by: Avi Kivity 
Signed-off-by: Marcelo Tosatti

KVM: Add x86_hyper_kvm to complete detect_hypervisor_platform check

2012-07-11T16:33:32+00:00

While debugging I noticed that unlike all the other hypervisor code in the
kernel, kvm does not have an entry for x86_hyper which is used in
detect_hypervisor_platform() which results in a nice printk in the
syslog.  This is only really a stub function but it
does make kvm more consistent with the other hypervisors.

Signed-off-by: Prarit Bhargava 
Cc: Avi Kivity 
Cc: Gleb Natapov 
Cc: Alex Williamson 
Cc: Konrad Rzeszutek Wilk 
Cc: Marcelo Tostatti 
Cc: kvm@vger.kernel.org
Signed-off-by: Avi Kivity

x86, hyper: Change hypervisor detection order

2011-07-08T23:22:29+00:00

Detect Xen before HyperV because in Viridian compatibility mode Xen
presents itself as HyperV.  Move Xen to the top since it seems more
likely that Xen would emulate VMware than vice versa.

Signed-off-by: Anupam Chanda 
Link: http://lkml.kernel.org/r/1310150570-26810-1-git-send-email-achanda@nicira.com
Acked-by: Stefano Stabellini 
Acked-by: Yaozu (Eddie) Dong 
Reviewed-by: H. Peter Anvin 
Signed-off-by: H. Peter Anvin

Introduce CONFIG_XEN_PVHVM compile option

2010-07-29T18:11:33+00:00

This patch introduce a CONFIG_XEN_PVHVM compile time option to
enable/disable Xen PV on HVM support.

Signed-off-by: Stefano Stabellini

xen/pvhvm: fix build problem when !CONFIG_XEN

2010-07-27T06:13:28+00:00

x86_hyper_xen_hvm is only defined when Xen is enabled in the kernel
config.

Signed-off-by: Jeremy Fitzhardinge

x86: early PV on HVM features initialization.

2010-07-22T23:45:35+00:00

Initialize basic pv on hvm features adding a new Xen HVM specific
hypervisor_x86 structure.

Don't try to initialize xen-kbdfront and xen-fbfront when running on HVM
because the backends are not available.

Signed-off-by: Stefano Stabellini 
Signed-off-by: Sheng Yang 
Signed-off-by: Yaozu (Eddie) Dong 
Signed-off-by: Jeremy Fitzhardinge