linux.git/arch/x86/kernel/kvm.c, branch v4.16

KVM: x86: Fix pv tlb flush dependencies

2018-03-28T13:53:34+00:00

PV TLB FLUSH can only be turned on when steal time is enabled.
The condition got reversed during conflict resolution.

Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Signed-off-by: Wanpeng Li 
Fixes: 4f2f61fc5071 ("KVM: X86: Avoid traversing all the cpus for pv tlb flush when steal time is disabled")
[Rebased on top of kvm/master and reworded the commit message. - Radim]
Signed-off-by: Radim Krčmář

KVM: X86: Avoid traversing all the cpus for pv tlb flush when steal time is disabled

2018-02-24T00:43:49+00:00

Avoid traversing all the cpus for pv tlb flush when steal time
is disabled since pv tlb flush depends on the field in steal time
for shared data.

Cc: Paolo Bonzini 
Cc: Radim KrÄmÃ¡Å™ 
Signed-off-by: Wanpeng Li 
Signed-off-by: Paolo Bonzini

x86/kvm: Make parse_no_xxx __init for kvm

2018-02-24T00:43:48+00:00

The early_param() is only called during kernel initialization, So Linux
marks the functions of it with __init macro to save memory.

But it forgot to mark the parse_no_kvmapf/stealacc/kvmclock_vsyscall,
So, Make them __init as well.

Cc: Paolo Bonzini 
Cc: rkrcmar@redhat.com
Cc: kvm@vger.kernel.org
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Juergen Gross 
Cc: x86@kernel.org
Signed-off-by: Dou Liyang 
Signed-off-by: Paolo Bonzini

KVM: x86: fix backward migration with async_PF

2018-02-24T00:43:48+00:00

Guests on new hypersiors might set KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT
bit when enabling async_PF, but this bit is reserved on old hypervisors,
which results in a failure upon migration.

To avoid breaking different cases, we are checking for CPUID feature bit
before enabling the feature and nothing else.

Fixes: 52a5c155cf79 ("KVM: async_pf: Let guest support delivery of async_pf from guest mode")
Cc: 
Reviewed-by: Wanpeng Li 
Reviewed-by: David Hildenbrand 
Signed-off-by: Radim Krčmář 
Signed-off-by: Paolo Bonzini

KVM: X86: use paravirtualized TLB Shootdown

2018-01-16T15:34:13+00:00

Remote TLB flush does a busy wait which is fine in bare-metal
scenario. But with-in the guest, the vcpus might have been pre-empted or
blocked. In this scenario, the initator vcpu would end up busy-waiting
for a long amount of time; it also consumes CPU unnecessarily to wake
up the target of the shootdown.

This patch set adds support for KVM's new paravirtualized TLB flush;
remote TLB flush does not wait for vcpus that are sleeping, instead
KVM will flush the TLB as soon as the vCPU starts running again.

The improvement is clearly visible when the host is overcommitted; in this
case, the PV TLB flush (in addition to avoiding the wait on the main CPU)
prevents preempted vCPUs from stealing precious execution time from the
running ones.

Testing on a Xeon Gold 6142 2.6GHz 2 sockets, 32 cores, 64 threads,
so 64 pCPUs, and each VM is 64 vCPUs.

ebizzy -M
              vanilla    optimized     boost
1VM            46799       48670         4%
2VM            23962       42691        78%
3VM            16152       37539       132%

Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: Peter Zijlstra 
Signed-off-by: Wanpeng Li 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Radim Krčmář

KVM: X86: Add KVM_VCPU_PREEMPTED

2018-01-16T15:34:13+00:00

The next patch will add another bit to the preempted field in
kvm_steal_time.  Define a constant for bit 0 (the only one that is
currently used).

Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: Peter Zijlstra 
Signed-off-by: Wanpeng Li 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Radim Krčmář

Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-11-14T01:04:36+00:00

Pull x86 platform updates from Ingo Molnar:
 "The main changes in this cycle were:

   - a refactoring of the early virt init code by merging 'struct
     x86_hyper' into 'struct x86_platform' and 'struct x86_init', which
     allows simplifications and also the addition of a new
     ->guest_late_init() callback. (Juergen Gross)

   - timer_setup() conversion of the UV code (Kees Cook)"

* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/virt/xen: Use guest_late_init to detect Xen PVH guest
  x86/virt, x86/platform: Add ->guest_late_init() callback to hypervisor_x86 structure
  x86/virt, x86/acpi: Add test for ACPI_FADT_NO_VGA
  x86/virt: Add enum for hypervisors to replace x86_hyper
  x86/virt, x86/platform: Merge 'struct x86_hyper' into 'struct x86_platform' and 'struct x86_init'
  x86/platform/UV: Convert timers to use timer_setup()

x86/virt, x86/platform: Add ->guest_late_init() callback to hypervisor_x86 structure

2017-11-10T09:03:13+00:00

Add a new guest_late_init callback to the hypervisor_x86 structure. It
will replace the current kvm_guest_init() call which is changed to
make use of the new callback.

Signed-off-by: Juergen Gross 
Acked-by: Thomas Gleixner 
Acked-by: Paolo Bonzini 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: kvm@vger.kernel.org
Cc: rkrcmar@redhat.com
Link: http://lkml.kernel.org/r/20171109132739.23465-5-jgross@suse.com
Signed-off-by: Ingo Molnar

x86/virt: Add enum for hypervisors to replace x86_hyper

2017-11-10T09:03:12+00:00

The x86_hyper pointer is only used for checking whether a virtual
device is supporting the hypervisor the system is running on.

Use an enum for that purpose instead and drop the x86_hyper pointer.

Signed-off-by: Juergen Gross 
Acked-by: Thomas Gleixner 
Acked-by: Xavier Deguillard 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: akataria@vmware.com
Cc: arnd@arndb.de
Cc: boris.ostrovsky@oracle.com
Cc: devel@linuxdriverproject.org
Cc: dmitry.torokhov@gmail.com
Cc: gregkh@linuxfoundation.org
Cc: haiyangz@microsoft.com
Cc: kvm@vger.kernel.org
Cc: kys@microsoft.com
Cc: linux-graphics-maintainer@vmware.com
Cc: linux-input@vger.kernel.org
Cc: moltmann@vmware.com
Cc: pbonzini@redhat.com
Cc: pv-drivers@vmware.com
Cc: rkrcmar@redhat.com
Cc: sthemmin@microsoft.com
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20171109132739.23465-3-jgross@suse.com
Signed-off-by: Ingo Molnar

x86/virt, x86/platform: Merge 'struct x86_hyper' into 'struct x86_platform' and 'struct x86_init'

2017-11-10T09:03:12+00:00

Instead of x86_hyper being either NULL on bare metal or a pointer to a
struct hypervisor_x86 in case of the kernel running as a guest merge
the struct into x86_platform and x86_init.

This will remove the need for wrappers making it hard to find out what
is being called. With dummy functions added for all callbacks testing
for a NULL function pointer can be removed, too.

Suggested-by: Ingo Molnar 
Signed-off-by: Juergen Gross 
Acked-by: Thomas Gleixner 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: akataria@vmware.com
Cc: boris.ostrovsky@oracle.com
Cc: devel@linuxdriverproject.org
Cc: haiyangz@microsoft.com
Cc: kvm@vger.kernel.org
Cc: kys@microsoft.com
Cc: pbonzini@redhat.com
Cc: rkrcmar@redhat.com
Cc: rusty@rustcorp.com.au
Cc: sthemmin@microsoft.com
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20171109132739.23465-2-jgross@suse.com
Signed-off-by: Ingo Molnar