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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 4bd518f1598d ("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>
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When installing new memslots, KVM sets bit 0 of the generation number to
indicate that an update is in-progress. Until the update is complete,
there are no guarantees as to whether a vCPU will see the old or the new
memslots. Explicity prevent caching MMIO accesses so as to avoid using
an access cached from the old memslots after the new memslots have been
installed.
Note that it is unclear whether or not disabling caching during the
update window is strictly necessary as there is no definitive
documentation as to what ordering guarantees KVM provides with respect
to updating memslots. That being said, the MMIO spte code does not
allow reusing sptes created while an update is in-progress, and the
associated documentation explicitly states:
We do not want to use an MMIO sptes created with an odd generation
number, ... If KVM is unlucky and creates an MMIO spte while the
low bit is 1, the next access to the spte will always be a cache miss.
At the very least, disabling the per-vCPU MMIO cache during updates will
make its behavior consistent with the MMIO spte behavior and
documentation.
Fixes: 56f17dd3fbc4 ("kvm: x86: fix stale mmio cache bug")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The check to detect a wrap of the MMIO generation explicitly looks for a
generation number of zero. Now that unique memslots generation numbers
are assigned to each address space, only address space 0 will get a
generation number of exactly zero when wrapping. E.g. when address
space 1 goes from 0x7fffe to 0x80002, the MMIO generation number will
wrap to 0x2. Adjust the MMIO generation to strip the address space
modifier prior to checking for a wrap.
Fixes: 4bd518f1598d ("KVM: use separate generations for each address space")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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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: e59dbe09f8e6 ("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>
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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.
Signed-off-by: Ben Gardon <bgardon@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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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.
Signed-off-by: Ben Gardon <bgardon@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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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 x86, they include:
vcpu->arch.pio_data
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>
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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>
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The preemption timer can be started even if there is a vmentry
failure during or after loading guest state. That is pointless,
move the call after all conditions have been checked.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Previously, 'commit f99e3daf94ff ("KVM: x86: Add Intel PT
virtualization work mode")' work mode' offered framework
to support Intel PT virtualization. However, the patch has
some typos in vmx_vmentry_ctrl() and vmx_vmexit_ctrl(), e.g.
used wrong flags and wrong variable, which will cause the
VM entry failure later.
Fixes: 'commit f99e3daf94ff ("KVM: x86: Add Intel PT virtualization work mode")'
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Ensure that the VCPU free path goes through vmx_leave_nested and
thus nested_vmx_vmexit, so that the cancellation of the timer does
not have to be in free_nested. In addition, because some paths through
nested_vmx_vmexit do not go through sync_vmcs12, the cancellation of
the timer is moved there.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Some Posted-Interrupts from passthrough devices may be lost or
overwritten when the vCPU is in runnable state.
The SN (Suppress Notification) of PID (Posted Interrupt Descriptor) will
be set when the vCPU is preempted (vCPU in KVM_MP_STATE_RUNNABLE state
but not running on physical CPU). If a posted interrupt coming at this
time, the irq remmaping facility will set the bit of PIR (Posted
Interrupt Requests) without ON (Outstanding Notification).
So this interrupt can't be sync to APIC virtualization register and
will not be handled by Guest because ON is zero.
Signed-off-by: Luwei Kang <luwei.kang@intel.com>
[Eliminate the pi_clear_sn fast path. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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MOVDIR64B moves 64-bytes as direct-store with 64-bytes write atomicity.
Direct store is implemented by using write combining (WC) for writing
data directly into memory without caching the data.
Availability of the MOVDIR64B instruction is indicated by the presence
of the CPUID feature flag MOVDIR64B (CPUID.0x07.0x0:ECX[bit 28]).
This patch exposes the movdir64b feature to the guest.
The release document ref below link:
https://software.intel.com/sites/default/files/managed/c5/15/\
architecture-instruction-set-extensions-programming-reference.pdf
Signed-off-by: Liu Jingqi <jingqi.liu@intel.com>
Cc: Xu Tao <tao3.xu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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MOVDIRI moves doubleword or quadword from register to memory through
direct store which is implemented by using write combining (WC) for
writing data directly into memory without caching the data.
Availability of the MOVDIRI instruction is indicated by the presence of
the CPUID feature flag MOVDIRI(CPUID.0x07.0x0:ECX[bit 27]).
This patch exposes the movdiri feature to the guest.
The release document ref below link:
https://software.intel.com/sites/default/files/managed/c5/15/\
architecture-instruction-set-extensions-programming-reference.pdf
Signed-off-by: Liu Jingqi <jingqi.liu@intel.com>
Cc: Xu Tao <tao3.xu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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AMD's SME/SEV is no longer the only case which reduces supported
physical address bits, since Intel introduced Multi-key Total Memory
Encryption (MKTME), which repurposes high bits of physical address as
keyID, thus effectively shrinks supported physical address bits. To
cover both cases (and potential similar future features), kernel MM
introduced generic dynamaic physical address mask instead of hard-coded
__PHYSICAL_MASK in 'commit 94d49eb30e854 ("x86/mm: Decouple dynamic
__PHYSICAL_MASK from AMD SME")'. KVM should use that too.
Change PT64_BASE_ADDR_MASK to use kernel dynamic physical address mask
when it is enabled, instead of sme_clr. PT64_DIR_BASE_ADDR_MASK is also
deleted since it is not used at all.
Signed-off-by: Kai Huang <kai.huang@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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VMX is only accessible in protected mode, remove a confusing check
that causes the conditional to lack a final "else" branch.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Regarding segments with a limit==0xffffffff, the SDM officially states:
When the effective limit is FFFFFFFFH (4 GBytes), these accesses may
or may not cause the indicated exceptions. Behavior is
implementation-specific and may vary from one execution to another.
In practice, all CPUs that support VMX ignore limit checks for "flat
segments", i.e. an expand-up data or code segment with base=0 and
limit=0xffffffff. This is subtly different than wrapping the effective
address calculation based on the address size, as the flat segment
behavior also applies to accesses that would wrap the 4g boundary, e.g.
a 4-byte access starting at 0xffffffff will access linear addresses
0xffffffff, 0x0, 0x1 and 0x2.
Fixes: f9eb4af67c9d ("KVM: nVMX: VMX instructions: add checks for #GP/#SS exceptions")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The address size of an instruction affects the effective address, not
the virtual/linear address. The final address may still be truncated,
e.g. to 32-bits outside of long mode, but that happens irrespective of
the address size, e.g. a 32-bit address size can yield a 64-bit virtual
address when using FS/GS with a non-zero base.
Fixes: 064aea774768 ("KVM: nVMX: Decoding memory operands of VMX instructions")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The VMCS.EXIT_QUALIFCATION field reports the displacements of memory
operands for various instructions, including VMX instructions, as a
naturally sized unsigned value, but masks the value by the addr size,
e.g. given a ModRM encoded as -0x28(%ebp), the -0x28 displacement is
reported as 0xffffffd8 for a 32-bit address size. Despite some weird
wording regarding sign extension, the SDM explicitly states that bits
beyond the instructions address size are undefined:
In all cases, bits of this field beyond the instruction’s address
size are undefined.
Failure to sign extend the displacement results in KVM incorrectly
treating a negative displacement as a large positive displacement when
the address size of the VMX instruction is smaller than KVM's native
size, e.g. a 32-bit address size on a 64-bit KVM.
The very original decoding, added by commit 064aea774768 ("KVM: nVMX:
Decoding memory operands of VMX instructions"), sort of modeled sign
extension by truncating the final virtual/linear address for a 32-bit
address size. I.e. it messed up the effective address but made it work
by adjusting the final address.
When segmentation checks were added, the truncation logic was kept
as-is and no sign extension logic was introduced. In other words, it
kept calculating the wrong effective address while mostly generating
the correct virtual/linear address. As the effective address is what's
used in the segment limit checks, this results in KVM incorreclty
injecting #GP/#SS faults due to non-existent segment violations when
a nested VMM uses negative displacements with an address size smaller
than KVM's native address size.
Using the -0x28(%ebp) example, an EBP value of 0x1000 will result in
KVM using 0x100000fd8 as the effective address when checking for a
segment limit violation. This causes a 100% failure rate when running
a 32-bit KVM build as L1 on top of a 64-bit KVM L0.
Fixes: f9eb4af67c9d ("KVM: nVMX: VMX instructions: add checks for #GP/#SS exceptions")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The function svm_refresh_apicv_exec_ctrl() always returning prematurely
as kvm_vcpu_apicv_active() always return false when calling from
the function arch/x86/kvm/x86.c:kvm_vcpu_deactivate_apicv().
This is because the apicv_active is set to false just before calling
refresh_apicv_exec_ctrl().
Also, we need to mark VMCB_AVIC bit as dirty instead of VMCB_INTR.
So, fix svm_refresh_apicv_exec_ctrl() to properly deactivate AVIC.
Fixes: 67034bb9dd5e ('KVM: SVM: Add irqchip_split() checks before enabling AVIC')
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Currently apicv_active can be true even if in-kernel LAPIC
emulation is disabled. Avoid this by properly initializing
it in kvm_arch_vcpu_init, and then do not do anything to
deactivate APICv when it is actually not used
(Currently APICv is only deactivated by SynIC code that in turn
is only reachable when in-kernel LAPIC is in use. However, it is
cleaner if kvm_vcpu_deactivate_apicv avoids relying on this.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Current SVM AVIC driver makes two incorrect assumptions:
1. APIC LDR register cannot be zero
2. APIC DFR for all vCPUs must be the same
LDR=0 means the local APIC does not support logical destination mode.
Therefore, the driver should mark any previously assigned logical APIC ID
table entry as invalid, and return success. Also, DFR is specific to
a particular local APIC, and can be different among all vCPUs
(as observed on Windows 10).
These incorrect assumptions cause Windows 10 and FreeBSD VMs to fail
to boot with AVIC enabled. So, instead of flush the whole logical APIC ID
table, handle DFR and LDR for each vCPU independently.
Fixes: 18f40c53e10f ('svm: Add VMEXIT handlers for AVIC')
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: Julian Stecklina <jsteckli@amazon.de>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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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>
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VMs may show incorrect uptime and dmesg printk offsets on hypervisors with
unstable clock. The problem is produced when VM is rebooted without exiting
from qemu.
The fix is to calculate clock offset not only for stable clock but for
unstable clock as well, and use kvm_sched_clock_read() which substracts
the offset for both clocks.
This is safe, because pvclock_clocksource_read() does the right thing and
makes sure that clock always goes forward, so once offset is calculated
with unstable clock, we won't get new reads that are smaller than offset,
and thus won't get negative results.
Thank you Jon DeVree for helping to reproduce this issue.
Fixes: 857baa87b642 ("sched/clock: Enable sched clock early")
Cc: stable@vger.kernel.org
Reported-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Move the clearing of the common registers (not 64-bit-only) to the start
of the flow that clears registers holding guest state. This is
purely a cosmetic change so that the label doesn't point at a blank line
and a #define.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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...now that the sub-routine follows standard calling conventions.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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...to make it callable from C code.
Note that because KVM chooses to be ultra paranoid about guest register
values, all callee-save registers are still cleared after VM-Exit even
though the host's values are now reloaded from the stack.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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...to prepare for making the assembly sub-routine callable from C code.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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...to prepare for making the sub-routine callable from C code.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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...to prepare for making the sub-routine callable from C code. That
means returning the result in RAX. Since RAX will be used to return the
result, use it as the scratch register as well to make the code readable
and to document that the scratch register is more or less arbitrary.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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...now that the name is no longer usurped by a defunct helper function.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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...now that the code is no longer tagged with STACK_FRAME_NON_STANDARD.
Arguably, providing __vmx_vcpu_run() to break up vmx_vcpu_run() is
valuable on its own, but the previous split was purposely made as small
as possible to limit the effects STACK_FRAME_NON_STANDARD. In other
words, the current split is now completely arbitrary and likely not the
most logical.
This also allows renaming ____vmx_vcpu_run() to __vmx_vcpu_run() in a
future patch.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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As evidenced by the myriad patches leading up to this moment, using
an inline asm blob for vCPU-run is nothing short of horrific. It's also
been called "unholy", "an abomination" and likely a whole host of other
names that would violate the Code of Conduct if recorded here and now.
The code is relocated nearly verbatim, e.g. quotes, newlines, tabs and
__stringify need to be dropped, but other than those cosmetic changes
the only functional changees are to add the "call" and replace the final
"jmp" with a "ret".
Note that STACK_FRAME_NON_STANDARD is also dropped from __vmx_vcpu_run().
Suggested-by: Andi Kleen <ak@linux.intel.com>
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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...in preparation for moving to a proper assembly sub-routnine.
vCPU-run isn't a leaf function since it calls vmx_update_host_rsp()
and vmx_vmenter(). And since we need to save/restore RBP anyways,
unconditionally creating the frame costs a single MOV, i.e. don't
bother keying off CONFIG_FRAME_POINTER or using FRAME_BEGIN, etc...
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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...to prepare for moving the inline asm to a proper asm sub-routine.
Eliminating the immediates allows a nearly verbatim move, e.g. quotes,
newlines, tabs and __stringify need to be dropped, but other than those
cosmetic changes the only function change will be to replace the final
"jmp" with a "ret".
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Declaring the VCPU_REGS_* as enums allows for more robust C code, but it
prevents using the values in assembly files. Expliciting #define the
indices in an asm-friendly file to prepare for VMX moving its transition
code to a proper assembly file, but keep the enums for general usage.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The 'gpa_end' local variable is never used and let's remove it.
Cc: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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Since Suzuki K Poulose's work on Dynamic IPA support, KVM_PHYS_SHIFT will
be used only when machine_type's bits[7:0] equal to 0 (by default). Thus
the outdated comment should be fixed.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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There is a spelling mistake in a kvm_err error message. Fix it.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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For historical reasons, KVM/arm and KVM/arm64 have had different
entries in the MAINTAINER file. This makes little sense, as they are
maintained together.
On top of that, we have a bunch of talented people helping with
the reviewing, and they deserve to be mentioned in the consolidated
entry.
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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Currently, the Kbuild core manipulates header search paths in a crazy
way [1].
To fix this mess, I want all Makefiles to add explicit $(srctree)/ to
the search paths in the srctree. Some Makefiles are already written in
that way, but not all. The goal of this work is to make the notation
consistent, and finally get rid of the gross hacks.
Having whitespaces after -I does not matter since commit 48f6e3cf5bc6
("kbuild: do not drop -I without parameter").
[1]: https://patchwork.kernel.org/patch/9632347/
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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The header search path -I. in kernel Makefiles is very suspicious;
it allows the compiler to search for headers in the top of $(srctree),
where obviously no header file exists.
I was able to build without these extra header search paths.
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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As the comment block in include/trace/define_trace.h says,
TRACE_INCLUDE_PATH should be a relative path to the define_trace.h
../../virt/kvm/arm is the correct relative path.
../../../virt/kvm/arm is working by coincidence because the top
Makefile adds -I$(srctree)/arch/$(SRCARCH)/include as a header
search path, but we should not rely on it.
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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interrupt is pending
When a guest gets scheduled, KVM performs a "load" operation,
which for the timer includes evaluating the virtual "active" state
of the interrupt, and replicating it on the physical side. This
ensures that the deactivation in the guest will also take place
in the physical GIC distributor.
If the interrupt is not yet active, we flag it as inactive on the
physical side. This means that on restoring the timer registers,
if the timer has expired, we'll immediately take an interrupt.
That's absolutely fine, as the interrupt will then be flagged as
active on the physical side. What this assumes though is that we'll
enter the guest right after having taken the interrupt, and that
the guest will quickly ACK the interrupt, making it active at on
the virtual side.
It turns out that quite often, this assumption doesn't really hold.
The guest may be preempted on the back on this interrupt, either
from kernel space or whilst running at EL1 when a host interrupt
fires. When this happens, we repeat the whole sequence on the
next load (interrupt marked as inactive, timer registers restored,
interrupt fires). And if it takes a really long time for a guest
to activate the interrupt (as it does with nested virt), we end-up
with many such events in quick succession, leading to the guest only
making very slow progress.
This can also be seen with the number of virtual timer interrupt on the
host being far greater than the same number in the guest.
An easy way to fix this is to evaluate the timer state when performing
the "load" operation, just like we do when the interrupt actually fires.
If the timer has a pending virtual interrupt at this stage, then we
can safely flag the physical interrupt as being active, which prevents
spurious exits.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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On SMP ARM systems, cache maintenance by set/way should only ever be
done in the context of onlining or offlining CPUs, which is typically
done by bare metal firmware and never in a virtual machine. For this
reason, we trap set/way cache maintenance operations and replace them
with conditional flushing of the entire guest address space.
Due to this trapping, the set/way arguments passed into the set/way
ops are completely ignored, and thus irrelevant. This also means that
the set/way geometry is equally irrelevant, and we can simply report
it as 1 set and 1 way, so that legacy 32-bit ARM system software (i.e.,
the kind that only receives odd fixes) doesn't take a performance hit
due to the trapping when iterating over the cachelines.
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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We currently permit CPUs in the same system to deviate in the exact
topology of the caches, and we subsequently hide this fact from user
space by exposing a sanitised value of the cache type register CTR_EL0.
However, guests running under KVM see the bare value of CTR_EL0, which
could potentially result in issues with, e.g., JITs or other pieces of
code that are sensitive to misreported cache line sizes.
So let's start trapping cache ID instructions if there is a mismatch,
and expose the sanitised version of CTR_EL0 to guests. Note that CTR_EL0
is treated as an invariant to KVM user space, so update that part as well.
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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Move this little function to the header files for arm/arm64 so other
code can make use of it directly.
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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We are currently emulating two timers in two different ways. When we
add support for nested virtualization in the future, we are going to be
emulating either two timers in two diffferent ways, or four timers in a
single way.
We need a unified data structure to keep track of how we map virtual
state to physical state and we need to cleanup some of the timer code to
operate more independently on a struct arch_timer_context instead of
trying to consider the global state of the VCPU and recomputing all
state.
Co-written with Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
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VHE systems don't have to emulate the physical timer, we can simply
assign the EL1 physical timer directly to the VM as the host always
uses the EL2 timers.
In order to minimize the amount of cruft, AArch32 gets definitions for
the physical timer too, but is should be generally unused on this
architecture.
Co-written with Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
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Prepare for having 4 timer data structures (2 for now).
Move loaded to the cpu data structure and not the individual timer
structure, in preparation for assigning the EL1 phys timer as well.
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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