When a vpcu is about to block by calling kvm_vcpu_block, we call
back into the arch code to allow any form of synchronization that
may be required at this point (SVN stops the AVIC, ARM synchronises
the VMCR and enables GICv4 doorbells). But this synchronization
comes in quite late, as we've potentially waited for halt_poll_ns
to expire.
Instead, let's move kvm_arch_vcpu_blocking() to the beginning of
kvm_vcpu_block(), which on ARM has several benefits:
- VMCR gets synchronised early, meaning that any interrupt delivered
during the polling window will be evaluated with the correct guest
PMR
- GICv4 doorbells are enabled, which means that any guest interrupt
directly injected during that window will be immediately recognised
Tang Nianyao ran some tests on a GICv4 machine to evaluate such
change, and reported up to a 10% improvement for netperf:
<quote>
netperf result:
D06 as server, intel 8180 server as client
with change:
package 512 bytes - 5500 Mbits/s
package 64 bytes - 760 Mbits/s
without change:
package 512 bytes - 5000 Mbits/s
package 64 bytes - 710 Mbits/s
</quote>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
The same check is already done in kvm_is_reserved_pfn.
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.
Also, when doing this, change kvm_arch_create_vcpu_debugfs() to return
void instead of an integer, as we should not care at all about if this
function actually does anything or not.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <x86@kernel.org>
Cc: <kvm@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There is no need for this function as all arches have to implement
kvm_arch_create_vcpu_debugfs() no matter what. A #define symbol
let us actually simplify the code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
After commit d73eb57b80 (KVM: Boost vCPUs that are delivering interrupts), a
five years old bug is exposed. Running ebizzy benchmark in three 80 vCPUs VMs
on one 80 pCPUs Skylake server, a lot of rcu_sched stall warning splatting
in the VMs after stress testing:
INFO: rcu_sched detected stalls on CPUs/tasks: { 4 41 57 62 77} (detected by 15, t=60004 jiffies, g=899, c=898, q=15073)
Call Trace:
flush_tlb_mm_range+0x68/0x140
tlb_flush_mmu.part.75+0x37/0xe0
tlb_finish_mmu+0x55/0x60
zap_page_range+0x142/0x190
SyS_madvise+0x3cd/0x9c0
system_call_fastpath+0x1c/0x21
swait_active() sustains to be true before finish_swait() is called in
kvm_vcpu_block(), voluntarily preempted vCPUs are taken into account
by kvm_vcpu_on_spin() loop greatly increases the probability condition
kvm_arch_vcpu_runnable(vcpu) is checked and can be true, when APICv
is enabled the yield-candidate vCPU's VMCS RVI field leaks(by
vmx_sync_pir_to_irr()) into spinning-on-a-taken-lock vCPU's current
VMCS.
This patch fixes it by checking conservatively a subset of events.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: stable@vger.kernel.org
Fixes: 98f4a1467 (KVM: add kvm_arch_vcpu_runnable() test to kvm_vcpu_on_spin() loop)
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
preempted_in_kernel is updated in preempt_notifier when involuntary preemption
ocurrs, it can be stale when the voluntarily preempted vCPUs are taken into
account by kvm_vcpu_on_spin() loop. This patch lets it just check preempted_in_kernel
for involuntary preemption.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Inspired by commit 9cac38dd5d (KVM/s390: Set preempted flag during
vcpu wakeup and interrupt delivery), we want to also boost not just
lock holders but also vCPUs that are delivering interrupts. Most
smp_call_function_many calls are synchronous, so the IPI target vCPUs
are also good yield candidates. This patch introduces vcpu->ready to
boost vCPUs during wakeup and interrupt delivery time; unlike s390 we do
not reuse vcpu->preempted so that voluntarily preempted vCPUs are taken
into account by kvm_vcpu_on_spin, but vmx_vcpu_pi_put is not affected
(VT-d PI handles voluntary preemption separately, in pi_pre_block).
Testing on 80 HT 2 socket Xeon Skylake server, with 80 vCPUs VM 80GB RAM:
ebizzy -M
vanilla boosting improved
1VM 21443 23520 9%
2VM 2800 8000 180%
3VM 1800 3100 72%
Testing on my Haswell desktop 8 HT, with 8 vCPUs VM 8GB RAM, two VMs,
one running ebizzy -M, the other running 'stress --cpu 2':
w/ boosting + w/o pv sched yield(vanilla)
vanilla boosting improved
1570 4000 155%
w/ boosting + w/ pv sched yield(vanilla)
vanilla boosting improved
1844 5157 179%
w/o boosting, perf top in VM:
72.33% [kernel] [k] smp_call_function_many
4.22% [kernel] [k] call_function_i
3.71% [kernel] [k] async_page_fault
w/ boosting, perf top in VM:
38.43% [kernel] [k] smp_call_function_many
6.31% [kernel] [k] async_page_fault
6.13% libc-2.23.so [.] __memcpy_avx_unaligned
4.88% [kernel] [k] call_function_interrupt
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- Add support for chained PMU counters in guests
- Improve SError handling
- Handle Neoverse N1 erratum #1349291
- Allow side-channel mitigation status to be migrated
- Standardise most AArch64 system register accesses to msr_s/mrs_s
- Fix host MPIDR corruption on 32bit
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Merge tag 'kvm-arm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm updates for 5.3
- Add support for chained PMU counters in guests
- Improve SError handling
- Handle Neoverse N1 erratum #1349291
- Allow side-channel mitigation status to be migrated
- Standardise most AArch64 system register accesses to msr_s/mrs_s
- Fix host MPIDR corruption on 32bit
The field "page" is initialized to KVM_UNMAPPED_PAGE when it is not used
(i.e. when the memory lives outside kernel control). So this check will
always end up using kunmap even for memremap regions.
Fixes: e45adf665a ("KVM: Introduce a new guest mapping API")
Cc: stable@vger.kernel.org
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Based on 1 normalized pattern(s):
this work is licensed under the terms of the gnu gpl version 2 see
the copying file in the top level directory
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 35 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.797835076@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It doesn't seem as if there is any particular need for kvm_lock to be a
spinlock, so convert the lock to a mutex so that sleepable functions (in
particular cond_resched()) can be called while holding it.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a wrapper to invoke kvm_arch_check_processor_compat() so that the
boilerplate ugliness of checking virtualization support on all CPUs is
hidden from the arch specific code. x86's implementation in particular
is quite heinous, as it unnecessarily propagates the out-param pattern
into kvm_x86_ops.
While the x86 specific issue could be resolved solely by changing
kvm_x86_ops, make the change for all architectures as returning a value
directly is prettier and technically more robust, e.g. s390 doesn't set
the out param, which could lead to subtle breakage in the (highly
unlikely) scenario where the out-param was not pre-initialized by the
caller.
Opportunistically annotate svm_check_processor_compat() with __init.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM_CAP_MAX_VCPU_ID is currently always reporting KVM_MAX_VCPU_ID on all
architectures. However, on s390x, the amount of usable CPUs is determined
during runtime - it is depending on the features of the machine the code
is running on. Since we are using the vcpu_id as an index into the SCA
structures that are defined by the hardware (see e.g. the sca_add_vcpu()
function), it is not only the amount of CPUs that is limited by the hard-
ware, but also the range of IDs that we can use.
Thus KVM_CAP_MAX_VCPU_ID must be determined during runtime on s390x, too.
So the handling of KVM_CAP_MAX_VCPU_ID has to be moved from the common
code into the architecture specific code, and on s390x we have to return
the same value here as for KVM_CAP_MAX_VCPUS.
This problem has been discovered with the kvm_create_max_vcpus selftest.
With this change applied, the selftest now passes on s390x, too.
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20190523164309.13345-9-thuth@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We also need to fence the memunmap part.
Fixes: e45adf665a ("KVM: Introduce a new guest mapping API")
Fixes: d30b214d1d (kvm: fix compilation on s390)
Cc: Michal Kubecek <mkubecek@suse.cz>
Cc: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
WARNING: CPU: 0 PID: 13554 at kvm/arch/x86/kvm//../../../virt/kvm/kvm_main.c:4183 kvm_resume+0x3c/0x40 [kvm]
CPU: 0 PID: 13554 Comm: step_after_susp Tainted: G OE 5.1.0-rc4+ #1
RIP: 0010:kvm_resume+0x3c/0x40 [kvm]
Call Trace:
syscore_resume+0x63/0x2d0
suspend_devices_and_enter+0x9d1/0xa40
pm_suspend+0x33a/0x3b0
state_store+0x82/0xf0
kobj_attr_store+0x12/0x20
sysfs_kf_write+0x4b/0x60
kernfs_fop_write+0x120/0x1a0
__vfs_write+0x1b/0x40
vfs_write+0xcd/0x1d0
ksys_write+0x5f/0xe0
__x64_sys_write+0x1a/0x20
do_syscall_64+0x6f/0x6c0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Commit ca84d1a24 (KVM: x86: Add clock sync request to hardware enable) mentioned
that "we always hold kvm_lock when hardware_enable is called. The one place that
doesn't need to worry about it is resume, as resuming a frozen CPU, the spinlock
won't be taken." However, commit 6706dae9 (virt/kvm: Replace spin_is_locked() with
lockdep) introduces a bug, it asserts when the lock is not held which is contrary
to the original goal.
This patch fixes it by WARN_ON when the lock is held.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Fixes: 6706dae9 ("virt/kvm: Replace spin_is_locked() with lockdep")
[Wrap with #ifdef CONFIG_LOCKDEP - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* POWER: support for direct access to the POWER9 XIVE interrupt controller,
memory and performance optimizations.
* x86: support for accessing memory not backed by struct page, fixes and refactoring
* Generic: dirty page tracking improvements
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"ARM:
- support for SVE and Pointer Authentication in guests
- PMU improvements
POWER:
- support for direct access to the POWER9 XIVE interrupt controller
- memory and performance optimizations
x86:
- support for accessing memory not backed by struct page
- fixes and refactoring
Generic:
- dirty page tracking improvements"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (155 commits)
kvm: fix compilation on aarch64
Revert "KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU"
kvm: x86: Fix L1TF mitigation for shadow MMU
KVM: nVMX: Disable intercept for FS/GS base MSRs in vmcs02 when possible
KVM: PPC: Book3S: Remove useless checks in 'release' method of KVM device
KVM: PPC: Book3S HV: XIVE: Fix spelling mistake "acessing" -> "accessing"
KVM: PPC: Book3S HV: Make sure to load LPID for radix VCPUs
kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete
tests: kvm: Add tests for KVM_SET_NESTED_STATE
KVM: nVMX: KVM_SET_NESTED_STATE - Tear down old EVMCS state before setting new state
tests: kvm: Add tests for KVM_CAP_MAX_VCPUS and KVM_CAP_MAX_CPU_ID
tests: kvm: Add tests to .gitignore
KVM: Introduce KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
KVM: Fix kvm_clear_dirty_log_protect off-by-(minus-)one
KVM: Fix the bitmap range to copy during clear dirty
KVM: arm64: Fix ptrauth ID register masking logic
KVM: x86: use direct accessors for RIP and RSP
KVM: VMX: Use accessors for GPRs outside of dedicated caching logic
KVM: x86: Omit caching logic for always-available GPRs
kvm, x86: Properly check whether a pfn is an MMIO or not
...
Commit e45adf665a ("KVM: Introduce a new guest mapping API", 2019-01-31)
introduced a build failure on aarch64 defconfig:
$ make -j$(nproc) ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- O=out defconfig \
Image.gz
...
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:
In function '__kvm_map_gfn':
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:1763:9: error:
implicit declaration of function 'memremap'; did you mean 'memset_p'?
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:1763:46: error:
'MEMREMAP_WB' undeclared (first use in this function)
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:
In function 'kvm_vcpu_unmap':
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:1795:3: error:
implicit declaration of function 'memunmap'; did you mean 'vm_munmap'?
because these functions are declared in <linux/io.h> rather than <asm/io.h>,
and the former was being pulled in already on x86 but not on aarch64.
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- Fix a bug, fix a spelling mistake, remove some useless code.
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Merge tag 'kvm-ppc-next-5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD
PPC KVM update for 5.2
* Support for guests to access the new POWER9 XIVE interrupt controller
hardware directly, reducing interrupt latency and overhead for guests.
* In-kernel implementation of the H_PAGE_INIT hypercall.
* Reduce memory usage of sparsely-populated IOMMU tables.
* Several bug fixes.
Second PPC KVM update for 5.2
* Fix a bug, fix a spelling mistake, remove some useless code.
Use the mmu_notifier_range_blockable() helper function instead of directly
dereferencing the range->blockable field. This is done to make it easier
to change the mmu_notifier range field.
This patch is the outcome of the following coccinelle patch:
%<-------------------------------------------------------------------
@@
identifier I1, FN;
@@
FN(..., struct mmu_notifier_range *I1, ...) {
<...
-I1->blockable
+mmu_notifier_range_blockable(I1)
...>
}
------------------------------------------------------------------->%
spatch --in-place --sp-file blockable.spatch --dir .
Link: http://lkml.kernel.org/r/20190326164747.24405-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no need to test for the device pointer validity when releasing
a KVM device. The file descriptor should identify it safely.
Fixes: 2bde9b3ec8 ("KVM: Introduce a 'release' method for KVM devices")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The previous KVM_CAP_MANUAL_DIRTY_LOG_PROTECT has some problem which
blocks the correct usage from userspace. Obsolete the old one and
introduce a new capability bit for it.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Just imaging the case where num_pages < BITS_PER_LONG, then the loop
will be skipped while it shouldn't.
Signed-off-by: Peter Xu <peterx@redhat.com>
Fixes: 2a31b9db15
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_dirty_bitmap_bytes() will return the size of the dirty bitmap of
the memslot rather than the size of bitmap passed over from the ioctl.
Here for KVM_CLEAR_DIRTY_LOG we should only copy exactly the size of
bitmap that covers kvm_clear_dirty_log.num_pages.
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 2a31b9db15
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In KVM, specially for nested guests, there is a dominant pattern of:
=> map guest memory -> do_something -> unmap guest memory
In addition to all this unnecessarily noise in the code due to boiler plate
code, most of the time the mapping function does not properly handle memory
that is not backed by "struct page". This new guest mapping API encapsulate
most of this boiler plate code and also handles guest memory that is not
backed by "struct page".
The current implementation of this API is using memremap for memory that is
not backed by a "struct page" which would lead to a huge slow-down if it
was used for high-frequency mapping operations. The API does not have any
effect on current setups where guest memory is backed by a "struct page".
Further patches are going to also introduce a pfn-cache which would
significantly improve the performance of the memremap case.
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
is_dirty has been renamed to flush, but the comment for it is
outdated. And the description about @flush parameter for
kvm_clear_dirty_log_protect() is missing, add it in this patch
as well.
Signed-off-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If a memory slot's size is not a multiple of 64 pages (256K), then
the KVM_CLEAR_DIRTY_LOG API is unusable: clearing the final 64 pages
either requires the requested page range to go beyond memslot->npages,
or requires log->num_pages to be unaligned, and kvm_clear_dirty_log_protect
requires log->num_pages to be both in range and aligned.
To allow this case, allow log->num_pages not to be a multiple of 64 if
it ends exactly on the last page of the slot.
Reported-by: Peter Xu <peterx@redhat.com>
Fixes: 98938aa8ed ("KVM: validate userspace input in kvm_clear_dirty_log_protect()", 2019-01-02)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- VSIE crypto fixes
- new guest features for gen15
- disable halt polling for nested virtualization with overcommit
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Merge tag 'kvm-s390-next-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD
KVM: s390: Features and fixes for 5.2
- VSIE crypto fixes
- new guest features for gen15
- disable halt polling for nested virtualization with overcommit
If a memory slot's size is not a multiple of 64 pages (256K), then
the KVM_CLEAR_DIRTY_LOG API is unusable: clearing the final 64 pages
either requires the requested page range to go beyond memslot->npages,
or requires log->num_pages to be unaligned, and kvm_clear_dirty_log_protect
requires log->num_pages to be both in range and aligned.
To allow this case, allow log->num_pages not to be a multiple of 64 if
it ends exactly on the last page of the slot.
Reported-by: Peter Xu <peterx@redhat.com>
Fixes: 98938aa8ed ("KVM: validate userspace input in kvm_clear_dirty_log_protect()", 2019-01-02)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When a P9 sPAPR VM boots, the CAS negotiation process determines which
interrupt mode to use (XICS legacy or XIVE native) and invokes a
machine reset to activate the chosen mode.
To be able to switch from one interrupt mode to another, we introduce
the capability to release a KVM device without destroying the VM. The
KVM device interface is extended with a new 'release' method which is
called when the file descriptor of the device is closed.
Once 'release' is called, the 'destroy' method will not be called
anymore as the device is removed from the device list of the VM.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Some KVM devices will want to handle special mappings related to the
underlying HW. For instance, the XIVE interrupt controller of the
POWER9 processor has MMIO pages for thread interrupt management and
for interrupt source control that need to be exposed to the guest when
the OS has the required support.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
There are cases where halt polling is unwanted. For example when running
KVM on an over committed LPAR we rather want to give back the CPU to
neighbour LPARs instead of polling. Let us provide a callback that
allows architectures to disable polling.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
All architectures except MIPS were defining it in the same way,
and memory slots are handled entirely by common code so there
is no point in keeping the definition per-architecture.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM's API requires thats ioctls must be issued from the same process
that created the VM. In other words, userspace can play games with a
VM's file descriptors, e.g. fork(), SCM_RIGHTS, etc..., but only the
creator can do anything useful. Explicitly reject device ioctls that
are issued by a process other than the VM's creator, and update KVM's
API documentation to extend its requirements to device ioctls.
Fixes: 852b6d57dc ("kvm: add device control API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
for 32-bit guests
s390: interrupt cleanup, introduction of the Guest Information Block,
preparation for processor subfunctions in cpu models
PPC: bug fixes and improvements, especially related to machine checks
and protection keys
x86: many, many cleanups, including removing a bunch of MMU code for
unnecessary optimizations; plus AVIC fixes.
Generic: memcg accounting
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"ARM:
- some cleanups
- direct physical timer assignment
- cache sanitization for 32-bit guests
s390:
- interrupt cleanup
- introduction of the Guest Information Block
- preparation for processor subfunctions in cpu models
PPC:
- bug fixes and improvements, especially related to machine checks
and protection keys
x86:
- many, many cleanups, including removing a bunch of MMU code for
unnecessary optimizations
- AVIC fixes
Generic:
- memcg accounting"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (147 commits)
kvm: vmx: fix formatting of a comment
KVM: doc: Document the life cycle of a VM and its resources
MAINTAINERS: Add KVM selftests to existing KVM entry
Revert "KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range()"
KVM: PPC: Book3S: Add count cache flush parameters to kvmppc_get_cpu_char()
KVM: PPC: Fix compilation when KVM is not enabled
KVM: Minor cleanups for kvm_main.c
KVM: s390: add debug logging for cpu model subfunctions
KVM: s390: implement subfunction processor calls
arm64: KVM: Fix architecturally invalid reset value for FPEXC32_EL2
KVM: arm/arm64: Remove unused timer variable
KVM: PPC: Book3S: Improve KVM reference counting
KVM: PPC: Book3S HV: Fix build failure without IOMMU support
Revert "KVM: Eliminate extra function calls in kvm_get_dirty_log_protect()"
x86: kvmguest: use TSC clocksource if invariant TSC is exposed
KVM: Never start grow vCPU halt_poll_ns from value below halt_poll_ns_grow_start
KVM: Expose the initial start value in grow_halt_poll_ns() as a module parameter
KVM: grow_halt_poll_ns() should never shrink vCPU halt_poll_ns
KVM: x86/mmu: Consolidate kvm_mmu_zap_all() and kvm_mmu_zap_mmio_sptes()
KVM: x86/mmu: WARN if zapping a MMIO spte results in zapping children
...
debugfs can now report an error code if something went wrong instead of
just NULL. So if the return value is to be used as a "real" dentry, it
needs to be checked if it is an error before dereferencing it.
This is now happening because of ff9fb72bc0 ("debugfs: return error
values, not NULL"). syzbot has found a way to trigger multiple debugfs
files attempting to be created, which fails, and then the error code
gets passed to dentry_path_raw() which obviously does not like it.
Reported-by: Eric Biggers <ebiggers@kernel.org>
Reported-and-tested-by: syzbot+7857962b4d45e602b8ad@syzkaller.appspotmail.com
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch contains two minor cleanups: firstly it puts exported symbol
for kvm_io_bus_write() by following the function definition; secondly it
removes a redundant blank line.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The value of "dirty_bitmap[i]" is already check before setting its value
to mask. The following check of "mask" is redundant. The check of "mask" was
introduced by commit 58d2930f4e ("KVM: Eliminate extra function calls in
kvm_get_dirty_log_protect()"), revert it.
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
grow_halt_poll_ns() have a strange behaviour in case
(vcpu->halt_poll_ns != 0) &&
(vcpu->halt_poll_ns < halt_poll_ns_grow_start).
In this case, vcpu->halt_poll_ns will be multiplied by grow factor
(halt_poll_ns_grow) which will require several grow iteration in order
to reach a value bigger than halt_poll_ns_grow_start.
This means that growing vcpu->halt_poll_ns from value of 0 is slower
than growing it from a positive value less than halt_poll_ns_grow_start.
Which is misleading and inaccurate.
Fix issue by changing grow_halt_poll_ns() to set vcpu->halt_poll_ns
to halt_poll_ns_grow_start in any case that
(vcpu->halt_poll_ns < halt_poll_ns_grow_start).
Regardless if vcpu->halt_poll_ns is 0.
use READ_ONCE to get a consistent number for all cases.
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Nir Weiner <nir.weiner@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The hard-coded value 10000 in grow_halt_poll_ns() stands for the initial
start value when raising up vcpu->halt_poll_ns.
It actually sets the first timeout to the first polling session.
This value has significant effect on how tolerant we are to outliers.
On the standard case, higher value is better - we will spend more time
in the polling busyloop, handle events/interrupts faster and result
in better performance.
But on outliers it puts us in a busy loop that does nothing.
Even if the shrink factor is zero, we will still waste time on the first
iteration.
The optimal value changes between different workloads. It depends on
outliers rate and polling sessions length.
As this value has significant effect on the dynamic halt-polling
algorithm, it should be configurable and exposed.
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Nir Weiner <nir.weiner@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
grow_halt_poll_ns() have a strange behavior in case
(halt_poll_ns_grow == 0) && (vcpu->halt_poll_ns != 0).
In this case, vcpu->halt_pol_ns will be set to zero.
That results in shrinking instead of growing.
Fix issue by changing grow_halt_poll_ns() to not modify
vcpu->halt_poll_ns in case halt_poll_ns_grow is zero
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Nir Weiner <nir.weiner@oracle.com>
Suggested-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
...now that KVM won't explode by moving it out of bit 0. Using bit 63
eliminates the need to jump over bit 0, e.g. when calculating a new
memslots generation or when propagating the memslots generation to an
MMIO spte.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
x86 captures a subset of the memslot generation (19 bits) in its MMIO
sptes so that it can expedite emulated MMIO handling by checking only
the releveant spte, i.e. doesn't need to do a full page fault walk.
Because the MMIO sptes capture only 19 bits (due to limited space in
the sptes), there is a non-zero probability that the MMIO generation
could wrap, e.g. after 500k memslot updates. Since normal usage is
extremely unlikely to result in 500k memslot updates, a hack was added
by commit 69c9ea93ea ("KVM: MMU: init kvm generation close to mmio
wrap-around value") to offset the MMIO generation in order to trigger
a wraparound, e.g. after 150 memslot updates.
When separate memslot generation sequences were assigned to each
address space, commit 00f034a12f ("KVM: do not bias the generation
number in kvm_current_mmio_generation") moved the offset logic into the
initialization of the memslot generation itself so that the per-address
space bit(s) were not dropped/corrupted by the MMIO shenanigans.
Remove the offset hack for three reasons:
- While it does exercise x86's kvm_mmu_invalidate_mmio_sptes(), simply
wrapping the generation doesn't actually test the interesting case
of having stale MMIO sptes with the new generation number, e.g. old
sptes with a generation number of 0.
- Triggering kvm_mmu_invalidate_mmio_sptes() prematurely makes its
performance rather important since the probability of invalidating
MMIO sptes jumps from "effectively never" to "fairly likely". This
limits what can be done in future patches, e.g. to simplify the
invalidation code, as doing so without proper caution could lead to
a noticeable performance regression.
- Forcing the memslots generation, which is a 64-bit number, to wrap
prevents KVM from assuming the memslots generation will never wrap.
This in turn prevents KVM from using an arbitrary bit for the
"update in-progress" flag, e.g. using bit 63 would immediately
collide with using a large value as the starting generation number.
The "update in-progress" flag is effectively forced into bit 0 so
that it's (subtly) taken into account when incrementing the
generation.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM uses bit 0 of the memslots generation as an "update in-progress"
flag, which is used by x86 to prevent caching MMIO access while the
memslots are changing. Although the intended behavior is flag-like,
e.g. MMIO sptes intentionally drop the in-progress bit so as to avoid
caching data from in-flux memslots, the implementation oftentimes treats
the bit as part of the generation number itself, e.g. incrementing the
generation increments twice, once to set the flag and once to clear it.
Prior to commit 4bd518f159 ("KVM: use separate generations for
each address space"), incorporating the "update in-progress" bit into
the generation number largely made sense, e.g. "real" generations are
even, "bogus" generations are odd, most code doesn't need to be aware of
the bit, etc...
Now that unique memslots generation numbers are assigned to each address
space, stealthing the in-progress status into the generation number
results in a wide variety of subtle code, e.g. kvm_create_vm() jumps
over bit 0 when initializing the memslots generation without any hint as
to why.
Explicitly define the flag and convert as much code as possible (which
isn't much) to actually treat it like a flag. This paves the way for
eventually using a different bit for "update in-progress" so that it can
be a flag in truth instead of a awkward extension to the generation
number.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_arch_memslots_updated() is at this point in time an x86-specific
hook for handling MMIO generation wraparound. x86 stashes 19 bits of
the memslots generation number in its MMIO sptes in order to avoid
full page fault walks for repeat faults on emulated MMIO addresses.
Because only 19 bits are used, wrapping the MMIO generation number is
possible, if unlikely. kvm_arch_memslots_updated() alerts x86 that
the generation has changed so that it can invalidate all MMIO sptes in
case the effective MMIO generation has wrapped so as to avoid using a
stale spte, e.g. a (very) old spte that was created with generation==0.
Given that the purpose of kvm_arch_memslots_updated() is to prevent
consuming stale entries, it needs to be called before the new generation
is propagated to memslots. Invalidating the MMIO sptes after updating
memslots means that there is a window where a vCPU could dereference
the new memslots generation, e.g. 0, and incorrectly reuse an old MMIO
spte that was created with (pre-wrap) generation==0.
Fixes: e59dbe09f8 ("KVM: Introduce kvm_arch_memslots_updated()")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There are many KVM kernel memory allocations which are tied to the life of
the VM process and should be charged to the VM process's cgroup. If the
allocations aren't tied to the process, the OOM killer will not know
that killing the process will free the associated kernel memory.
Add __GFP_ACCOUNT flags to many of the allocations which are not yet being
charged to the VM process's cgroup.
Tested:
Ran all kvm-unit-tests on a 64 bit Haswell machine, the patch
introduced no new failures.
Ran a kernel memory accounting test which creates a VM to touch
memory and then checks that the kernel memory allocated for the
process is within certain bounds.
With this patch we account for much more of the vmalloc and slab memory
allocated for the VM.
There remain a few allocations which should be charged to the VM's
cgroup but are not. In they include:
vcpu->run
kvm->coalesced_mmio_ring
There allocations are unaccounted in this patch because they are mapped
to userspace, and accounting them to a cgroup causes problems. This
should be addressed in a future patch.
Signed-off-by: Ben Gardon <bgardon@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull the latest RCU tree from Paul E. McKenney:
- Additional cleanups after RCU flavor consolidation
- Grace-period forward-progress cleanups and improvements
- Documentation updates
- Miscellaneous fixes
- spin_is_locked() conversions to lockdep
- SPDX changes to RCU source and header files
- SRCU updates
- Torture-test updates, including nolibc updates and moving
nolibc to tools/include
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Marc Zyngier