Commit Graph

983271 Commits

Author SHA1 Message Date
Andrew Scull
c4b000c392 KVM: arm64: Fix nVHE hyp panic host context restore
When panicking from the nVHE hyp and restoring the host context, x29 is
expected to hold a pointer to the host context. This wasn't being done
so fix it to make sure there's a valid pointer the host context being
used.

Rather than passing a boolean indicating whether or not the host context
should be restored, instead pass the pointer to the host context. NULL
is passed to indicate that no context should be restored.

Fixes: a2e102e20f ("KVM: arm64: nVHE: Handle hyp panics")
Cc: stable@vger.kernel.org
Signed-off-by: Andrew Scull <ascull@google.com>
[maz: partial rewrite to fit 5.12-rc1]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210219122406.1337626-1-ascull@google.com
Message-Id: <20210305185254.3730990-4-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-06 04:18:40 -05:00
Will Deacon
31948332d5 KVM: arm64: Avoid corrupting vCPU context register in guest exit
Commit 7db2153047 ("KVM: arm64: Restore hyp when panicking in guest
context") tracks the currently running vCPU, clearing the pointer to
NULL on exit from a guest.

Unfortunately, the use of 'set_loaded_vcpu' clobbers x1 to point at the
kvm_hyp_ctxt instead of the vCPU context, causing the subsequent RAS
code to go off into the weeds when it saves the DISR assuming that the
CPU context is embedded in a struct vCPU.

Leave x1 alone and use x3 as a temporary register instead when clearing
the vCPU on the guest exit path.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Andrew Scull <ascull@google.com>
Cc: <stable@vger.kernel.org>
Fixes: 7db2153047 ("KVM: arm64: Restore hyp when panicking in guest context")
Suggested-by: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210226181211.14542-1-will@kernel.org
Message-Id: <20210305185254.3730990-3-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-06 04:18:40 -05:00
Suzuki K Poulose
b96b0c5de6 KVM: arm64: nvhe: Save the SPE context early
The nVHE KVM hyp drains and disables the SPE buffer, before
entering the guest, as the EL1&0 translation regime
is going to be loaded with that of the guest.

But this operation is performed way too late, because :
  - The owning translation regime of the SPE buffer
    is transferred to EL2. (MDCR_EL2_E2PB == 0)
  - The guest Stage1 is loaded.

Thus the flush could use the host EL1 virtual address,
but use the EL2 translations instead of host EL1, for writing
out any cached data.

Fix this by moving the SPE buffer handling early enough.
The restore path is doing the right thing.

Fixes: 014c4c77aa ("KVM: arm64: Improve debug register save/restore flow")
Cc: stable@vger.kernel.org
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210302120345.3102874-1-suzuki.poulose@arm.com
Message-Id: <20210305185254.3730990-2-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-06 04:18:39 -05:00
Muhammad Usama Anjum
4691453406 kvm: x86: use NULL instead of using plain integer as pointer
Sparse warnings removed:
warning: Using plain integer as NULL pointer

Signed-off-by: Muhammad Usama Anjum <musamaanjum@gmail.com>
Message-Id: <20210305180816.GA488770@LEGION>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-06 04:18:39 -05:00
Sean Christopherson
99840a7545 KVM: SVM: Connect 'npt' module param to KVM's internal 'npt_enabled'
Directly connect the 'npt' param to the 'npt_enabled' variable so that
runtime adjustments to npt_enabled are reflected in sysfs.  Move the
!PAE restriction to a runtime check to ensure NPT is forced off if the
host is using 2-level paging, and add a comment explicitly stating why
NPT requires a 64-bit kernel or a kernel with PAE enabled.

Opportunistically switch the param to octal permissions.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210305021637.3768573-1-seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-05 08:33:15 -05:00
Sean Christopherson
beda430177 KVM: x86: Ensure deadline timer has truly expired before posting its IRQ
When posting a deadline timer interrupt, open code the checks guarding
__kvm_wait_lapic_expire() in order to skip the lapic_timer_int_injected()
check in kvm_wait_lapic_expire().  The injection check will always fail
since the interrupt has not yet be injected.  Moving the call after
injection would also be wrong as that wouldn't actually delay delivery
of the IRQ if it is indeed sent via posted interrupt.

Fixes: 010fd37fdd ("KVM: LAPIC: Reduce world switch latency caused by timer_advance_ns")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210305021808.3769732-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-05 08:30:21 -05:00
Babu Moger
9e46f6c6c9 KVM: SVM: Clear the CR4 register on reset
This problem was reported on a SVM guest while executing kexec.
Kexec fails to load the new kernel when the PCID feature is enabled.

When kexec starts loading the new kernel, it starts the process by
resetting the vCPU's and then bringing each vCPU online one by one.
The vCPU reset is supposed to reset all the register states before the
vCPUs are brought online. However, the CR4 register is not reset during
this process. If this register is already setup during the last boot,
all the flags can remain intact. The X86_CR4_PCIDE bit can only be
enabled in long mode. So, it must be enabled much later in SMP
initialization.  Having the X86_CR4_PCIDE bit set during SMP boot can
cause a boot failures.

Fix the issue by resetting the CR4 register in init_vmcb().

Signed-off-by: Babu Moger <babu.moger@amd.com>
Message-Id: <161471109108.30811.6392805173629704166.stgit@bmoger-ubuntu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-02 14:39:11 -05:00
David Woodhouse
30b5c851af KVM: x86/xen: Add support for vCPU runstate information
This is how Xen guests do steal time accounting. The hypervisor records
the amount of time spent in each of running/runnable/blocked/offline
states.

In the Xen accounting, a vCPU is still in state RUNSTATE_running while
in Xen for a hypercall or I/O trap, etc. Only if Xen explicitly schedules
does the state become RUNSTATE_blocked. In KVM this means that even when
the vCPU exits the kvm_run loop, the state remains RUNSTATE_running.

The VMM can explicitly set the vCPU to RUNSTATE_blocked by using the
KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT attribute, and can also use
KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST to retrospectively add a given
amount of time to the blocked state and subtract it from the running
state.

The state_entry_time corresponds to get_kvmclock_ns() at the time the
vCPU entered the current state, and the total times of all four states
should always add up to state_entry_time.

Co-developed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20210301125309.874953-2-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-02 14:30:54 -05:00
David Woodhouse
7d7c5f76e5 KVM: x86/xen: Fix return code when clearing vcpu_info and vcpu_time_info
When clearing the per-vCPU shared regions, set the return value to zero
to indicate success. This was causing spurious errors to be returned to
userspace on soft reset.

Also add a paranoid BUILD_BUG_ON() for compat structure compatibility.

Fixes: 0c165b3c01 ("KVM: x86/xen: Allow reset of Xen attributes")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20210301125309.874953-1-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-02 14:30:54 -05:00
Aaron Lewis
6528fc0a11 selftests: kvm: Mmap the entire vcpu mmap area
The vcpu mmap area may consist of more than just the kvm_run struct.
Allocate enough space for the entire vcpu mmap area. Without this, on
x86, the PIO page, for example, will be missing.  This is problematic
when dealing with an unhandled exception from the guest as the exception
vector will be incorrectly reported as 0x0.

Message-Id: <20210210165035.3712489-1-aaronlewis@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Co-developed-by: Steve Rutherford <srutherford@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-02 14:30:53 -05:00
Kai Huang
7d2cdad0da KVM: Documentation: Fix index for KVM_CAP_PPC_DAWR1
It should be 7.23 instead of 7.22, which has already been taken by
KVM_CAP_X86_BUS_LOCK_EXIT.

Signed-off-by: Kai Huang <kai.huang@intel.com>
Message-Id: <20210226094832.380394-1-kai.huang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-02 14:30:53 -05:00
Paolo Bonzini
b59b153d10 KVM: x86: allow compiling out the Xen hypercall interface
The Xen hypercall interface adds to the attack surface of the hypervisor
and will be used quite rarely.  Allow compiling it out.

Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-02 14:30:45 -05:00
Paolo Bonzini
c462f859f8 KVM: xen: flush deferred static key before checking it
A missing flush would cause the static branch to trigger incorrectly.

Cc: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-26 05:13:02 -05:00
Sean Christopherson
44ac5958a6 KVM: x86/mmu: Set SPTE_AD_WRPROT_ONLY_MASK if and only if PML is enabled
Check that PML is actually enabled before setting the mask to force a
SPTE to be write-protected.  The bits used for the !AD_ENABLED case are
in the upper half of the SPTE.  With 64-bit paging and EPT, these bits
are ignored, but with 32-bit PAE paging they are reserved.  Setting them
for L2 SPTEs without checking PML breaks NPT on 32-bit KVM.

Fixes: 1f4e5fc83a ("KVM: x86: fix nested guest live migration with PML")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210225204749.1512652-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-26 04:43:29 -05:00
Wanpeng Li
919f4ebc59 KVM: x86: hyper-v: Fix Hyper-V context null-ptr-deref
Reported by syzkaller:

    KASAN: null-ptr-deref in range [0x0000000000000140-0x0000000000000147]
    CPU: 1 PID: 8370 Comm: syz-executor859 Not tainted 5.11.0-syzkaller #0
    RIP: 0010:synic_get arch/x86/kvm/hyperv.c:165 [inline]
    RIP: 0010:kvm_hv_set_sint_gsi arch/x86/kvm/hyperv.c:475 [inline]
    RIP: 0010:kvm_hv_irq_routing_update+0x230/0x460 arch/x86/kvm/hyperv.c:498
    Call Trace:
     kvm_set_irq_routing+0x69b/0x940 arch/x86/kvm/../../../virt/kvm/irqchip.c:223
     kvm_vm_ioctl+0x12d0/0x2800 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3959
     vfs_ioctl fs/ioctl.c:48 [inline]
     __do_sys_ioctl fs/ioctl.c:753 [inline]
     __se_sys_ioctl fs/ioctl.c:739 [inline]
     __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
     do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
     entry_SYSCALL_64_after_hwframe+0x44/0xae

Hyper-V context is lazily allocated until Hyper-V specific MSRs are accessed
or SynIC is enabled. However, the syzkaller testcase sets irq routing table
directly w/o enabling SynIC. This results in null-ptr-deref when accessing
SynIC Hyper-V context. This patch fixes it.

syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=163342ccd00000

Reported-by: syzbot+6987f3b2dbd9eda95f12@syzkaller.appspotmail.com
Fixes: 8f014550df ("KVM: x86: hyper-v: Make Hyper-V emulation enablement conditional")
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1614326399-5762-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-26 03:16:50 -05:00
Dongli Zhang
ffe76c24c5 KVM: x86: remove misplaced comment on active_mmu_pages
The 'mmu_page_hash' is used as hash table while 'active_mmu_pages' is a
list. Remove the misplaced comment as it's mostly stating the obvious
anyways.

Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210226061945.1222-1-dongli.zhang@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-26 03:03:29 -05:00
Chenyi Qiang
96564d7773 KVM: Documentation: rectify rst markup in kvm_run->flags
Commit c32b1b896d ("KVM: X86: Add the Document for
KVM_CAP_X86_BUS_LOCK_EXIT") added a new flag in kvm_run->flags
documentation, and caused warning in make htmldocs:

  Documentation/virt/kvm/api.rst:5004: WARNING: Unexpected indentation
  Documentation/virt/kvm/api.rst:5004: WARNING: Inline emphasis start-string without end-string

Fix this rst markup issue.

Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Message-Id: <20210226075541.27179-1-chenyi.qiang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-26 03:03:12 -05:00
Paolo Bonzini
e2a0fcac6b Documentation: kvm: fix messy conversion from .txt to .rst
Building the documentation gives a warning that the KVM_PPC_RESIZE_HPT_PREPARE
label is defined twice.  The root cause is that the KVM_PPC_RESIZE_HPT_PREPARE
API is present twice, the second being a mix of the prepare and commit APIs.
Fix it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-26 03:02:22 -05:00
Sean Christopherson
2df8d3807c KVM: SVM: Fix nested VM-Exit on #GP interception handling
Fix the interpreation of nested_svm_vmexit()'s return value when
synthesizing a nested VM-Exit after intercepting an SVM instruction while
L2 was running.  The helper returns '0' on success, whereas a return
value of '0' in the exit handler path means "exit to userspace".  The
incorrect return value causes KVM to exit to userspace without filling
the run state, e.g. QEMU logs "KVM: unknown exit, hardware reason 0".

Fixes: 14c2bf81fc ("KVM: SVM: Fix #GP handling for doubly-nested virtualization")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210224005627.657028-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-25 05:13:05 -05:00
Like Xu
67b45af946 KVM: vmx/pmu: Fix dummy check if lbr_desc->event is created
If lbr_desc->event is successfully created, the intel_pmu_create_
guest_lbr_event() will return 0, otherwise it will return -ENOENT,
and then jump to LBR msrs dummy handling.

Fixes: 1b5ac3226a ("KVM: vmx/pmu: Pass-through LBR msrs when the guest LBR event is ACTIVE")
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Message-Id: <20210223013958.1280444-1-like.xu@linux.intel.com>
[Add "< 0" and PTR_ERR to make the code clearer. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-23 12:07:35 -05:00
David Stevens
4a42d848db KVM: x86/mmu: Consider the hva in mmu_notifier retry
Track the range being invalidated by mmu_notifier and skip page fault
retries if the fault address is not affected by the in-progress
invalidation. Handle concurrent invalidations by finding the minimal
range which includes all ranges being invalidated. Although the combined
range may include unrelated addresses and cannot be shrunk as individual
invalidation operations complete, it is unlikely the marginal gains of
proper range tracking are worth the additional complexity.

The primary benefit of this change is the reduction in the likelihood of
extreme latency when handing a page fault due to another thread having
been preempted while modifying host virtual addresses.

Signed-off-by: David Stevens <stevensd@chromium.org>
Message-Id: <20210222024522.1751719-3-stevensd@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-22 13:16:53 -05:00
Sean Christopherson
5f8a7cf25a KVM: x86/mmu: Skip mmu_notifier check when handling MMIO page fault
Don't retry a page fault due to an mmu_notifier invalidation when
handling a page fault for a GPA that did not resolve to a memslot, i.e.
an MMIO page fault.  Invalidations from the mmu_notifier signal a change
in a host virtual address (HVA) mapping; without a memslot, there is no
HVA and thus no possibility that the invalidation is relevant to the
page fault being handled.

Note, the MMIO vs. memslot generation checks handle the case where a
pending memslot will create a memslot overlapping the faulting GPA.  The
mmu_notifier checks are orthogonal to memslot updates.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210222024522.1751719-2-stevensd@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-22 13:13:30 -05:00
Lukas Bulwahn
356c7558d4 KVM: Documentation: rectify rst markup in KVM_GET_SUPPORTED_HV_CPUID
Commit c21d54f030 ("KVM: x86: hyper-v: allow KVM_GET_SUPPORTED_HV_CPUID
as a system ioctl") added an enumeration in the KVM_GET_SUPPORTED_HV_CPUID
documentation improperly for rst, and caused new warnings in make htmldocs:

  Documentation/virt/kvm/api.rst:4536: WARNING: Unexpected indentation.
  Documentation/virt/kvm/api.rst:4538: WARNING: Block quote ends without a blank line; unexpected unindent.

Fix that issue and another historic rst markup issue from the initial
rst conversion in the KVM_GET_SUPPORTED_HV_CPUID documentation.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Message-Id: <20210104095938.24838-1-lukas.bulwahn@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-22 13:12:31 -05:00
Paolo Bonzini
d2df592fd8 KVM: nSVM: prepare guest save area while is_guest_mode is true
Right now, enter_svm_guest_mode is calling nested_prepare_vmcb_save and
nested_prepare_vmcb_control.  This results in is_guest_mode being false
until the end of nested_prepare_vmcb_control.

This is a problem because nested_prepare_vmcb_save can in turn cause
changes to the intercepts and these have to be applied to the "host VMCB"
(stored in svm->nested.hsave) and then merged with the VMCB12 intercepts
into svm->vmcb.

In particular, without this change we forget to set the CR0 read and CR0
write intercepts when running a real mode L2 guest with NPT disabled.
The guest is therefore able to see the CR0.PG bit that KVM sets to
enable "paged real mode".  This patch fixes the svm.flat mode_switch
test case with npt=0.  There are no other problematic calls in
nested_prepare_vmcb_save.

Moving is_guest_mode to the end is done since commit 06fc777269
("KVM: SVM: Activate nested state only when guest state is complete",
2010-04-25).  However, back then KVM didn't grab a different VMCB
when updating the intercepts, it had already copied/merged L1's stuff
to L0's VMCB, and then updated L0's VMCB regardless of is_nested().
Later recalc_intercepts was introduced in commit 384c636843
("KVM: SVM: Add function to recalculate intercept masks", 2011-01-12).
This introduced the bug, because recalc_intercepts now throws away
the intercept manipulations that svm_set_cr0 had done in the meanwhile
to svm->vmcb.

[1] https://lore.kernel.org/kvm/1266493115-28386-1-git-send-email-joerg.roedel@amd.com/

Reviewed-by: Sean Christopherson <seanjc@google.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-22 13:11:56 -05:00
Sean Christopherson
96ad91ae4e KVM: x86/mmu: Remove a variety of unnecessary exports
Remove several exports from the MMU that are no longer necessary.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-15-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:35 -05:00
Sean Christopherson
a1419f8b5b KVM: x86: Fold "write-protect large" use case into generic write-protect
Drop kvm_mmu_slot_largepage_remove_write_access() and refactor its sole
caller to use kvm_mmu_slot_remove_write_access().  Remove the now-unused
slot_handle_large_level() and slot_handle_all_level() helpers.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-14-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:35 -05:00
Sean Christopherson
b6e16ae5d9 KVM: x86/mmu: Don't set dirty bits when disabling dirty logging w/ PML
Stop setting dirty bits for MMU pages when dirty logging is disabled for
a memslot, as PML is now completely disabled when there are no memslots
with dirty logging enabled.

This means that spurious PML entries will be created for memslots with
dirty logging disabled if at least one other memslot has dirty logging
enabled.  However, spurious PML entries are already possible since
dirty bits are set only when a dirty logging is turned off, i.e. memslots
that are never dirty logged will have dirty bits cleared.

In the end, it's faster overall to eat a few spurious PML entries in the
window where dirty logging is being disabled across all memslots.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-13-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:35 -05:00
Makarand Sonare
a85863c2ec KVM: VMX: Dynamically enable/disable PML based on memslot dirty logging
Currently, if enable_pml=1 PML remains enabled for the entire lifetime
of the VM irrespective of whether dirty logging is enable or disabled.
When dirty logging is disabled, all the pages of the VM are manually
marked dirty, so that PML is effectively non-operational.  Setting
the dirty bits is an expensive operation which can cause severe MMU
lock contention in a performance sensitive path when dirty logging is
disabled after a failed or canceled live migration.

Manually setting dirty bits also fails to prevent PML activity if some
code path clears dirty bits, which can incur unnecessary VM-Exits.

In order to avoid this extra overhead, dynamically enable/disable PML
when dirty logging gets turned on/off for the first/last memslot.

Signed-off-by: Makarand Sonare <makarandsonare@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-12-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:34 -05:00
Sean Christopherson
52f4607940 KVM: x86: Further clarify the logic and comments for toggling log dirty
Add a sanity check in kvm_mmu_slot_apply_flags to assert that the
LOG_DIRTY_PAGES flag is indeed being toggled, and explicitly rely on
that holding true when zapping collapsible SPTEs.  Manipulating the
CPU dirty log (PML) and write-protection also relies on this assertion,
but that's not obvious in the current code.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-11-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:34 -05:00
Sean Christopherson
a018eba538 KVM: x86: Move MMU's PML logic to common code
Drop the facade of KVM's PML logic being vendor specific and move the
bits that aren't truly VMX specific into common x86 code.  The MMU logic
for dealing with PML is tightly coupled to the feature and to VMX's
implementation, bouncing through kvm_x86_ops obfuscates the code without
providing any meaningful separation of concerns or encapsulation.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:34 -05:00
Sean Christopherson
6dd03800b1 KVM: x86/mmu: Make dirty log size hook (PML) a value, not a function
Store the vendor-specific dirty log size in a variable, there's no need
to wrap it in a function since the value is constant after
hardware_setup() runs.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:33 -05:00
Sean Christopherson
2855f98265 KVM: x86/mmu: Expand on the comment in kvm_vcpu_ad_need_write_protect()
Expand the comment about need to use write-protection for nested EPT
when PML is enabled to clarify that the tagging is a nop when PML is
_not_ enabled.  Without the clarification, omitting the PML check looks
wrong at first^Wfifth glance.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:33 -05:00
Sean Christopherson
c3bb9a2083 KVM: nVMX: Disable PML in hardware when running L2
Unconditionally disable PML in vmcs02, KVM emulates PML purely in the
MMU, e.g. vmx_flush_pml_buffer() doesn't even try to copy the L2 GPAs
from vmcs02's buffer to vmcs12.  At best, enabling PML is a nop.  At
worst, it will cause vmx_flush_pml_buffer() to record bogus GFNs in the
dirty logs.

Initialize vmcs02.GUEST_PML_INDEX such that PML writes would trigger
VM-Exit if PML was somehow enabled, skip flushing the buffer for guest
mode since the index is bogus, and freak out if a PML full exit occurs
when L2 is active.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:32 -05:00
Sean Christopherson
9eba50f8d7 KVM: x86/mmu: Consult max mapping level when zapping collapsible SPTEs
When zapping SPTEs in order to rebuild them as huge pages, use the new
helper that computes the max mapping level to detect whether or not a
SPTE should be zapped.  Doing so avoids zapping SPTEs that can't
possibly be rebuilt as huge pages, e.g. due to hardware constraints,
memslot alignment, etc...

This also avoids zapping SPTEs that are still large, e.g. if migration
was canceled before write-protected huge pages were shattered to enable
dirty logging.  Note, such pages are still write-protected at this time,
i.e. a page fault VM-Exit will still occur.  This will hopefully be
addressed in a future patch.

Sadly, TDP MMU loses its const on the memslot, but that's a pervasive
problem that's been around for quite some time.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:28 -05:00
Sean Christopherson
0a234f5dd0 KVM: x86/mmu: Pass the memslot to the rmap callbacks
Pass the memslot to the rmap callbacks, it will be used when zapping
collapsible SPTEs to verify the memslot is compatible with hugepages
before zapping its SPTEs.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:12 -05:00
Sean Christopherson
1b6d9d9ed5 KVM: x86/mmu: Split out max mapping level calculation to helper
Factor out the logic for determining the maximum mapping level given a
memslot and a gpa.  The helper will be used when zapping collapsible
SPTEs when disabling dirty logging, e.g. to avoid zapping SPTEs that
can't possibly be rebuilt as hugepages.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:08:11 -05:00
Sean Christopherson
c060c72ffe KVM: x86/mmu: Expand collapsible SPTE zap for TDP MMU to ZONE_DEVICE and HugeTLB pages
Zap SPTEs that are backed by ZONE_DEVICE pages when zappings SPTEs to
rebuild them as huge pages in the TDP MMU.  ZONE_DEVICE huge pages are
managed differently than "regular" pages and are not compound pages.
Likewise, PageTransCompoundMap() will not detect HugeTLB, so switch
to PageCompound().

This matches the similar check in kvm_mmu_zap_collapsible_spte.

Cc: Ben Gardon <bgardon@google.com>
Fixes: 1488199856 ("kvm: x86/mmu: Support disabling dirty logging for the tdp MMU")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210213005015.1651772-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19 03:07:16 -05:00
Paolo Bonzini
78e550bad2 KVM: nVMX: no need to undo inject_page_fault change on nested vmexit
This is not needed because the tweak was done on the guest_mmu, while
nested_ept_uninit_mmu_context has just changed vcpu->arch.walk_mmu
back to the root_mmu.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-18 07:33:31 -05:00
Paolo Bonzini
a04aead144 KVM: nSVM: fix running nested guests when npt=0
In case of npt=0 on host, nSVM needs the same .inject_page_fault tweak
as VMX has, to make sure that shadow mmu faults are injected as vmexits.

It is not clear why this is needed at all, but for now keep the same
code as VMX and we'll fix it for both.

Based on a patch by Maxim Levitsky <mlevitsk@redhat.com>.

Fixes: 7c86663b68 ("KVM: nSVM: inject exceptions via svm_check_nested_events")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-18 07:33:30 -05:00
Maxim Levitsky
954f419ba8 KVM: nSVM: move nested vmrun tracepoint to enter_svm_guest_mode
This way trace will capture all the nested mode entries
(including entries after migration, and from smm)

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210217145718.1217358-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-18 07:33:30 -05:00
Maxim Levitsky
f5c59b575b KVM: VMX: read idt_vectoring_info a bit earlier
trace_kvm_exit prints this value (using vmx_get_exit_info)
so it makes sense to read it before the trace point.

Fixes: dcf068da7e ("KVM: VMX: Introduce generic fastpath handler")

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210217145718.1217358-2-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-18 07:33:29 -05:00
Sean Christopherson
1aaca37e1e KVM: VMX: Allow INVPCID in guest without PCID
Remove the restriction that prevents VMX from exposing INVPCID to the
guest without PCID also being exposed to the guest.  The justification of
the restriction is that INVPCID will #UD if it's disabled in the VMCS.
While that is a true statement, it's also true that RDTSCP will #UD if
it's disabled in the VMCS.  Neither of those things has any dependency
whatsoever on the guest being able to set CR4.PCIDE=1, which is what is
effectively allowed by exposing PCID to the guest.

Removing the bogus restriction aligns VMX with SVM, and also allows for
an interesting configuration.  INVPCID is that fastest way to do a global
TLB flush, e.g. see native_flush_tlb_global().  Allowing INVPCID without
PCID would let a guest use the expedited flush while also limiting the
number of ASIDs consumed by the guest.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210212003411.1102677-4-seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-18 07:33:29 -05:00
Sean Christopherson
e420333422 KVM: x86: Advertise INVPCID by default
Advertise INVPCID by default (if supported by the host kernel) instead
of having both SVM and VMX opt in.  INVPCID was opt in when it was a
VMX only feature so that KVM wouldn't prematurely advertise support
if/when it showed up in the kernel on AMD hardware.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210212003411.1102677-3-seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-18 07:33:29 -05:00
Sean Christopherson
0a8ed2eaac KVM: SVM: Intercept INVPCID when it's disabled to inject #UD
Intercept INVPCID if it's disabled in the guest, even when using NPT,
as KVM needs to inject #UD in this case.

Fixes: 4407a797e9 ("KVM: SVM: Enable INVPCID feature on AMD")
Cc: Babu Moger <babu.moger@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210212003411.1102677-2-seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-18 07:33:28 -05:00
Paolo Bonzini
bcd22e145b selftests: kvm: avoid uninitialized variable warning
The variable in practice will never be uninitialized, because the
loop will always go through at least one iteration.

In case it would not, make vcpu_get_cpuid report an assertion
failure.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-15 11:42:45 -05:00
Ignacio Alvarado
1838b06bf0 selftests: kvm: add hardware_disable test
This test launches 512 VMs in serial and kills them after a random
amount of time.

The test was original written to exercise KVM user notifiers in
the context of1650b4ebc99d:
- KVM: Disable irq while unregistering user notifier
- https://lore.kernel.org/kvm/CACXrx53vkO=HKfwWwk+fVpvxcNjPrYmtDZ10qWxFvVX_PTGp3g@mail.gmail.com/

Recently, this test piqued my interest because it proved useful to
for AMD SNP in exercising the "in-use" pages, described in APM section
15.36.12, "Running SNP-Active Virtual Machines".

Signed-off-by: Ignacio Alvarado <ikalvarado@google.com>
Signed-off-by: Marc Orr <marcorr@google.com>
Message-Id: <20210213001452.1719001-1-marcorr@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-15 11:42:36 -05:00
Paolo Bonzini
8c6e67bec3 KVM/arm64 updates for Linux 5.12
- Make the nVHE EL2 object relocatable, resulting in much more
   maintainable code
 - Handle concurrent translation faults hitting the same page
   in a more elegant way
 - Support for the standard TRNG hypervisor call
 - A bunch of small PMU/Debug fixes
 - Allow the disabling of symbol export from assembly code
 - Simplification of the early init hypercall handling
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Merge tag 'kvmarm-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for Linux 5.12

- Make the nVHE EL2 object relocatable, resulting in much more
  maintainable code
- Handle concurrent translation faults hitting the same page
  in a more elegant way
- Support for the standard TRNG hypervisor call
- A bunch of small PMU/Debug fixes
- Allow the disabling of symbol export from assembly code
- Simplification of the early init hypercall handling
2021-02-12 11:23:44 -05:00
Marc Zyngier
c93199e93e Merge branch 'kvm-arm64/pmu-debug-fixes-5.11' into kvmarm-master/next
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-02-12 14:08:41 +00:00
Marc Zyngier
8cb68a9d14 Merge branch 'kvm-arm64/rng-5.12' into kvmarm-master/next
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-02-12 14:08:25 +00:00
Marc Zyngier
e7ae2ecdc8 Merge branch 'kvm-arm64/hyp-reloc' into kvmarm-master/next
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-02-12 14:08:18 +00:00