<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/Documentation/virt, branch linux-5.12.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>KVM: X86: MMU: Use the correct inherited permissions to get shadow page</title>
<updated>2021-06-16T10:05:06+00:00</updated>
<author>
<name>Lai Jiangshan</name>
<email>laijs@linux.alibaba.com</email>
</author>
<published>2021-06-03T05:24:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7707f7244d813f8279143d5dfdee7a318801231b'/>
<id>7707f7244d813f8279143d5dfdee7a318801231b</id>
<content type='text'>
commit b1bd5cba3306691c771d558e94baa73e8b0b96b7 upstream.

When computing the access permissions of a shadow page, use the effective
permissions of the walk up to that point, i.e. the logic AND of its parents'
permissions.  Two guest PxE entries that point at the same table gfn need to
be shadowed with different shadow pages if their parents' permissions are
different.  KVM currently uses the effective permissions of the last
non-leaf entry for all non-leaf entries.  Because all non-leaf SPTEs have
full ("uwx") permissions, and the effective permissions are recorded only
in role.access and merged into the leaves, this can lead to incorrect
reuse of a shadow page and eventually to a missing guest protection page
fault.

For example, here is a shared pagetable:

   pgd[]   pud[]        pmd[]            virtual address pointers
                     /-&gt;pmd1(u--)-&gt;pte1(uw-)-&gt;page1 &lt;- ptr1 (u--)
        /-&gt;pud1(uw-)---&gt;pmd2(uw-)-&gt;pte2(uw-)-&gt;page2 &lt;- ptr2 (uw-)
   pgd-|           (shared pmd[] as above)
        \-&gt;pud2(u--)---&gt;pmd1(u--)-&gt;pte1(uw-)-&gt;page1 &lt;- ptr3 (u--)
                     \-&gt;pmd2(uw-)-&gt;pte2(uw-)-&gt;page2 &lt;- ptr4 (u--)

  pud1 and pud2 point to the same pmd table, so:
  - ptr1 and ptr3 points to the same page.
  - ptr2 and ptr4 points to the same page.

(pud1 and pud2 here are pud entries, while pmd1 and pmd2 here are pmd entries)

- First, the guest reads from ptr1 first and KVM prepares a shadow
  page table with role.access=u--, from ptr1's pud1 and ptr1's pmd1.
  "u--" comes from the effective permissions of pgd, pud1 and
  pmd1, which are stored in pt-&gt;access.  "u--" is used also to get
  the pagetable for pud1, instead of "uw-".

- Then the guest writes to ptr2 and KVM reuses pud1 which is present.
  The hypervisor set up a shadow page for ptr2 with pt-&gt;access is "uw-"
  even though the pud1 pmd (because of the incorrect argument to
  kvm_mmu_get_page in the previous step) has role.access="u--".

- Then the guest reads from ptr3.  The hypervisor reuses pud1's
  shadow pmd for pud2, because both use "u--" for their permissions.
  Thus, the shadow pmd already includes entries for both pmd1 and pmd2.

- At last, the guest writes to ptr4.  This causes no vmexit or pagefault,
  because pud1's shadow page structures included an "uw-" page even though
  its role.access was "u--".

Any kind of shared pagetable might have the similar problem when in
virtual machine without TDP enabled if the permissions are different
from different ancestors.

In order to fix the problem, we change pt-&gt;access to be an array, and
any access in it will not include permissions ANDed from child ptes.

The test code is: https://lore.kernel.org/kvm/20210603050537.19605-1-jiangshanlai@gmail.com/
Remember to test it with TDP disabled.

The problem had existed long before the commit 41074d07c78b ("KVM: MMU:
Fix inherited permissions for emulated guest pte updates"), and it
is hard to find which is the culprit.  So there is no fixes tag here.

Signed-off-by: Lai Jiangshan &lt;laijs@linux.alibaba.com&gt;
Message-Id: &lt;20210603052455.21023-1-jiangshanlai@gmail.com&gt;
Cc: stable@vger.kernel.org
Fixes: cea0f0e7ea54 ("[PATCH] KVM: MMU: Shadow page table caching")
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit b1bd5cba3306691c771d558e94baa73e8b0b96b7 upstream.

When computing the access permissions of a shadow page, use the effective
permissions of the walk up to that point, i.e. the logic AND of its parents'
permissions.  Two guest PxE entries that point at the same table gfn need to
be shadowed with different shadow pages if their parents' permissions are
different.  KVM currently uses the effective permissions of the last
non-leaf entry for all non-leaf entries.  Because all non-leaf SPTEs have
full ("uwx") permissions, and the effective permissions are recorded only
in role.access and merged into the leaves, this can lead to incorrect
reuse of a shadow page and eventually to a missing guest protection page
fault.

For example, here is a shared pagetable:

   pgd[]   pud[]        pmd[]            virtual address pointers
                     /-&gt;pmd1(u--)-&gt;pte1(uw-)-&gt;page1 &lt;- ptr1 (u--)
        /-&gt;pud1(uw-)---&gt;pmd2(uw-)-&gt;pte2(uw-)-&gt;page2 &lt;- ptr2 (uw-)
   pgd-|           (shared pmd[] as above)
        \-&gt;pud2(u--)---&gt;pmd1(u--)-&gt;pte1(uw-)-&gt;page1 &lt;- ptr3 (u--)
                     \-&gt;pmd2(uw-)-&gt;pte2(uw-)-&gt;page2 &lt;- ptr4 (u--)

  pud1 and pud2 point to the same pmd table, so:
  - ptr1 and ptr3 points to the same page.
  - ptr2 and ptr4 points to the same page.

(pud1 and pud2 here are pud entries, while pmd1 and pmd2 here are pmd entries)

- First, the guest reads from ptr1 first and KVM prepares a shadow
  page table with role.access=u--, from ptr1's pud1 and ptr1's pmd1.
  "u--" comes from the effective permissions of pgd, pud1 and
  pmd1, which are stored in pt-&gt;access.  "u--" is used also to get
  the pagetable for pud1, instead of "uw-".

- Then the guest writes to ptr2 and KVM reuses pud1 which is present.
  The hypervisor set up a shadow page for ptr2 with pt-&gt;access is "uw-"
  even though the pud1 pmd (because of the incorrect argument to
  kvm_mmu_get_page in the previous step) has role.access="u--".

- Then the guest reads from ptr3.  The hypervisor reuses pud1's
  shadow pmd for pud2, because both use "u--" for their permissions.
  Thus, the shadow pmd already includes entries for both pmd1 and pmd2.

- At last, the guest writes to ptr4.  This causes no vmexit or pagefault,
  because pud1's shadow page structures included an "uw-" page even though
  its role.access was "u--".

Any kind of shared pagetable might have the similar problem when in
virtual machine without TDP enabled if the permissions are different
from different ancestors.

In order to fix the problem, we change pt-&gt;access to be an array, and
any access in it will not include permissions ANDed from child ptes.

The test code is: https://lore.kernel.org/kvm/20210603050537.19605-1-jiangshanlai@gmail.com/
Remember to test it with TDP disabled.

The problem had existed long before the commit 41074d07c78b ("KVM: MMU:
Fix inherited permissions for emulated guest pte updates"), and it
is hard to find which is the culprit.  So there is no fixes tag here.

Signed-off-by: Lai Jiangshan &lt;laijs@linux.alibaba.com&gt;
Message-Id: &lt;20210603052455.21023-1-jiangshanlai@gmail.com&gt;
Cc: stable@vger.kernel.org
Fixes: cea0f0e7ea54 ("[PATCH] KVM: MMU: Shadow page table caching")
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>documentation/kvm: additional explanations on KVM_SET_BOOT_CPU_ID</title>
<updated>2021-03-19T09:31:32+00:00</updated>
<author>
<name>Emanuele Giuseppe Esposito</name>
<email>eesposit@redhat.com</email>
</author>
<published>2021-03-19T09:16:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9ce3746d64132a561bceab6421715e7c04e85074'/>
<id>9ce3746d64132a561bceab6421715e7c04e85074</id>
<content type='text'>
The ioctl KVM_SET_BOOT_CPU_ID fails when called after vcpu creation.
Add this explanation in the documentation.

Signed-off-by: Emanuele Giuseppe Esposito &lt;eesposit@redhat.com&gt;
Message-Id: &lt;20210319091650.11967-1-eesposit@redhat.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The ioctl KVM_SET_BOOT_CPU_ID fails when called after vcpu creation.
Add this explanation in the documentation.

Signed-off-by: Emanuele Giuseppe Esposito &lt;eesposit@redhat.com&gt;
Message-Id: &lt;20210319091650.11967-1-eesposit@redhat.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: x86: Protect userspace MSR filter with SRCU, and set atomically-ish</title>
<updated>2021-03-18T17:55:14+00:00</updated>
<author>
<name>Sean Christopherson</name>
<email>seanjc@google.com</email>
</author>
<published>2021-03-16T18:44:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b318e8decf6b9ef1bcf4ca06fae6d6a2cb5d5c5c'/>
<id>b318e8decf6b9ef1bcf4ca06fae6d6a2cb5d5c5c</id>
<content type='text'>
Fix a plethora of issues with MSR filtering by installing the resulting
filter as an atomic bundle instead of updating the live filter one range
at a time.  The KVM_X86_SET_MSR_FILTER ioctl() isn't truly atomic, as
the hardware MSR bitmaps won't be updated until the next VM-Enter, but
the relevant software struct is atomically updated, which is what KVM
really needs.

Similar to the approach used for modifying memslots, make arch.msr_filter
a SRCU-protected pointer, do all the work configuring the new filter
outside of kvm-&gt;lock, and then acquire kvm-&gt;lock only when the new filter
has been vetted and created.  That way vCPU readers either see the old
filter or the new filter in their entirety, not some half-baked state.

Yuan Yao pointed out a use-after-free in ksm_msr_allowed() due to a
TOCTOU bug, but that's just the tip of the iceberg...

  - Nothing is __rcu annotated, making it nigh impossible to audit the
    code for correctness.
  - kvm_add_msr_filter() has an unpaired smp_wmb().  Violation of kernel
    coding style aside, the lack of a smb_rmb() anywhere casts all code
    into doubt.
  - kvm_clear_msr_filter() has a double free TOCTOU bug, as it grabs
    count before taking the lock.
  - kvm_clear_msr_filter() also has memory leak due to the same TOCTOU bug.

The entire approach of updating the live filter is also flawed.  While
installing a new filter is inherently racy if vCPUs are running, fixing
the above issues also makes it trivial to ensure certain behavior is
deterministic, e.g. KVM can provide deterministic behavior for MSRs with
identical settings in the old and new filters.  An atomic update of the
filter also prevents KVM from getting into a half-baked state, e.g. if
installing a filter fails, the existing approach would leave the filter
in a half-baked state, having already committed whatever bits of the
filter were already processed.

[*] https://lkml.kernel.org/r/20210312083157.25403-1-yaoyuan0329os@gmail.com

Fixes: 1a155254ff93 ("KVM: x86: Introduce MSR filtering")
Cc: stable@vger.kernel.org
Cc: Alexander Graf &lt;graf@amazon.com&gt;
Reported-by: Yuan Yao &lt;yaoyuan0329os@gmail.com&gt;
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
Message-Id: &lt;20210316184436.2544875-2-seanjc@google.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix a plethora of issues with MSR filtering by installing the resulting
filter as an atomic bundle instead of updating the live filter one range
at a time.  The KVM_X86_SET_MSR_FILTER ioctl() isn't truly atomic, as
the hardware MSR bitmaps won't be updated until the next VM-Enter, but
the relevant software struct is atomically updated, which is what KVM
really needs.

Similar to the approach used for modifying memslots, make arch.msr_filter
a SRCU-protected pointer, do all the work configuring the new filter
outside of kvm-&gt;lock, and then acquire kvm-&gt;lock only when the new filter
has been vetted and created.  That way vCPU readers either see the old
filter or the new filter in their entirety, not some half-baked state.

Yuan Yao pointed out a use-after-free in ksm_msr_allowed() due to a
TOCTOU bug, but that's just the tip of the iceberg...

  - Nothing is __rcu annotated, making it nigh impossible to audit the
    code for correctness.
  - kvm_add_msr_filter() has an unpaired smp_wmb().  Violation of kernel
    coding style aside, the lack of a smb_rmb() anywhere casts all code
    into doubt.
  - kvm_clear_msr_filter() has a double free TOCTOU bug, as it grabs
    count before taking the lock.
  - kvm_clear_msr_filter() also has memory leak due to the same TOCTOU bug.

The entire approach of updating the live filter is also flawed.  While
installing a new filter is inherently racy if vCPUs are running, fixing
the above issues also makes it trivial to ensure certain behavior is
deterministic, e.g. KVM can provide deterministic behavior for MSRs with
identical settings in the old and new filters.  An atomic update of the
filter also prevents KVM from getting into a half-baked state, e.g. if
installing a filter fails, the existing approach would leave the filter
in a half-baked state, having already committed whatever bits of the
filter were already processed.

[*] https://lkml.kernel.org/r/20210312083157.25403-1-yaoyuan0329os@gmail.com

Fixes: 1a155254ff93 ("KVM: x86: Introduce MSR filtering")
Cc: stable@vger.kernel.org
Cc: Alexander Graf &lt;graf@amazon.com&gt;
Reported-by: Yuan Yao &lt;yaoyuan0329os@gmail.com&gt;
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
Message-Id: &lt;20210316184436.2544875-2-seanjc@google.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm</title>
<updated>2021-03-14T19:35:02+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-03-14T19:35:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9d0c8e793f0eb0613efe81d2cdca8c2efa0ad33c'/>
<id>9d0c8e793f0eb0613efe81d2cdca8c2efa0ad33c</id>
<content type='text'>
Pull KVM fixes from Paolo Bonzini:
 "More fixes for ARM and x86"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: LAPIC: Advancing the timer expiration on guest initiated write
  KVM: x86/mmu: Skip !MMU-present SPTEs when removing SP in exclusive mode
  KVM: kvmclock: Fix vCPUs &gt; 64 can't be online/hotpluged
  kvm: x86: annotate RCU pointers
  KVM: arm64: Fix exclusive limit for IPA size
  KVM: arm64: Reject VM creation when the default IPA size is unsupported
  KVM: arm64: Ensure I-cache isolation between vcpus of a same VM
  KVM: arm64: Don't use cbz/adr with external symbols
  KVM: arm64: Fix range alignment when walking page tables
  KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility
  KVM: arm64: Rename __vgic_v3_get_ich_vtr_el2() to __vgic_v3_get_gic_config()
  KVM: arm64: Don't access PMSELR_EL0/PMUSERENR_EL0 when no PMU is available
  KVM: arm64: Turn kvm_arm_support_pmu_v3() into a static key
  KVM: arm64: Fix nVHE hyp panic host context restore
  KVM: arm64: Avoid corrupting vCPU context register in guest exit
  KVM: arm64: nvhe: Save the SPE context early
  kvm: x86: use NULL instead of using plain integer as pointer
  KVM: SVM: Connect 'npt' module param to KVM's internal 'npt_enabled'
  KVM: x86: Ensure deadline timer has truly expired before posting its IRQ
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull KVM fixes from Paolo Bonzini:
 "More fixes for ARM and x86"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: LAPIC: Advancing the timer expiration on guest initiated write
  KVM: x86/mmu: Skip !MMU-present SPTEs when removing SP in exclusive mode
  KVM: kvmclock: Fix vCPUs &gt; 64 can't be online/hotpluged
  kvm: x86: annotate RCU pointers
  KVM: arm64: Fix exclusive limit for IPA size
  KVM: arm64: Reject VM creation when the default IPA size is unsupported
  KVM: arm64: Ensure I-cache isolation between vcpus of a same VM
  KVM: arm64: Don't use cbz/adr with external symbols
  KVM: arm64: Fix range alignment when walking page tables
  KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility
  KVM: arm64: Rename __vgic_v3_get_ich_vtr_el2() to __vgic_v3_get_gic_config()
  KVM: arm64: Don't access PMSELR_EL0/PMUSERENR_EL0 when no PMU is available
  KVM: arm64: Turn kvm_arm_support_pmu_v3() into a static key
  KVM: arm64: Fix nVHE hyp panic host context restore
  KVM: arm64: Avoid corrupting vCPU context register in guest exit
  KVM: arm64: nvhe: Save the SPE context early
  kvm: x86: use NULL instead of using plain integer as pointer
  KVM: SVM: Connect 'npt' module param to KVM's internal 'npt_enabled'
  KVM: x86: Ensure deadline timer has truly expired before posting its IRQ
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: arm64: Reject VM creation when the default IPA size is unsupported</title>
<updated>2021-03-12T15:42:57+00:00</updated>
<author>
<name>Marc Zyngier</name>
<email>maz@kernel.org</email>
</author>
<published>2021-03-11T10:00:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7d717558dd5ef10d28866750d5c24ff892ea3778'/>
<id>7d717558dd5ef10d28866750d5c24ff892ea3778</id>
<content type='text'>
KVM/arm64 has forever used a 40bit default IPA space, partially
due to its 32bit heritage (where the only choice is 40bit).

However, there are implementations in the wild that have a *cough*
much smaller *cough* IPA space, which leads to a misprogramming of
VTCR_EL2, and a guest that is stuck on its first memory access
if userspace dares to ask for the default IPA setting (which most
VMMs do).

Instead, blundly reject the creation of such VM, as we can't
satisfy the requirements from userspace (with a one-off warning).
Also clarify the boot warning, and document that the VM creation
will fail when an unsupported IPA size is provided.

Although this is an ABI change, it doesn't really change much
for userspace:

- the guest couldn't run before this change, but no error was
  returned. At least userspace knows what is happening.

- a memory slot that was accepted because it did fit the default
  IPA space now doesn't even get a chance to be registered.

The other thing that is left doing is to convince userspace to
actually use the IPA space setting instead of relying on the
antiquated default.

Fixes: 233a7cb23531 ("kvm: arm64: Allow tuning the physical address size for VM")
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: stable@vger.kernel.org
Reviewed-by: Andrew Jones &lt;drjones@redhat.com&gt;
Reviewed-by: Eric Auger &lt;eric.auger@redhat.com&gt;
Link: https://lore.kernel.org/r/20210311100016.3830038-2-maz@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
KVM/arm64 has forever used a 40bit default IPA space, partially
due to its 32bit heritage (where the only choice is 40bit).

However, there are implementations in the wild that have a *cough*
much smaller *cough* IPA space, which leads to a misprogramming of
VTCR_EL2, and a guest that is stuck on its first memory access
if userspace dares to ask for the default IPA setting (which most
VMMs do).

Instead, blundly reject the creation of such VM, as we can't
satisfy the requirements from userspace (with a one-off warning).
Also clarify the boot warning, and document that the VM creation
will fail when an unsupported IPA size is provided.

Although this is an ABI change, it doesn't really change much
for userspace:

- the guest couldn't run before this change, but no error was
  returned. At least userspace knows what is happening.

- a memory slot that was accepted because it did fit the default
  IPA space now doesn't even get a chance to be registered.

The other thing that is left doing is to convince userspace to
actually use the IPA space setting instead of relying on the
antiquated default.

Fixes: 233a7cb23531 ("kvm: arm64: Allow tuning the physical address size for VM")
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: stable@vger.kernel.org
Reviewed-by: Andrew Jones &lt;drjones@redhat.com&gt;
Reviewed-by: Eric Auger &lt;eric.auger@redhat.com&gt;
Link: https://lore.kernel.org/r/20210311100016.3830038-2-maz@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm</title>
<updated>2021-03-04T19:26:17+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-03-04T19:26:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cee407c5cc427a7d9b21ee964fbda613e368bdff'/>
<id>cee407c5cc427a7d9b21ee964fbda613e368bdff</id>
<content type='text'>
Pull KVM fixes from Paolo Bonzini:

 - Doc fixes

 - selftests fixes

 - Add runstate information to the new Xen support

 - Allow compiling out the Xen interface

 - 32-bit PAE without EPT bugfix

 - NULL pointer dereference bugfix

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: SVM: Clear the CR4 register on reset
  KVM: x86/xen: Add support for vCPU runstate information
  KVM: x86/xen: Fix return code when clearing vcpu_info and vcpu_time_info
  selftests: kvm: Mmap the entire vcpu mmap area
  KVM: Documentation: Fix index for KVM_CAP_PPC_DAWR1
  KVM: x86: allow compiling out the Xen hypercall interface
  KVM: xen: flush deferred static key before checking it
  KVM: x86/mmu: Set SPTE_AD_WRPROT_ONLY_MASK if and only if PML is enabled
  KVM: x86: hyper-v: Fix Hyper-V context null-ptr-deref
  KVM: x86: remove misplaced comment on active_mmu_pages
  KVM: Documentation: rectify rst markup in kvm_run-&gt;flags
  Documentation: kvm: fix messy conversion from .txt to .rst
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull KVM fixes from Paolo Bonzini:

 - Doc fixes

 - selftests fixes

 - Add runstate information to the new Xen support

 - Allow compiling out the Xen interface

 - 32-bit PAE without EPT bugfix

 - NULL pointer dereference bugfix

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: SVM: Clear the CR4 register on reset
  KVM: x86/xen: Add support for vCPU runstate information
  KVM: x86/xen: Fix return code when clearing vcpu_info and vcpu_time_info
  selftests: kvm: Mmap the entire vcpu mmap area
  KVM: Documentation: Fix index for KVM_CAP_PPC_DAWR1
  KVM: x86: allow compiling out the Xen hypercall interface
  KVM: xen: flush deferred static key before checking it
  KVM: x86/mmu: Set SPTE_AD_WRPROT_ONLY_MASK if and only if PML is enabled
  KVM: x86: hyper-v: Fix Hyper-V context null-ptr-deref
  KVM: x86: remove misplaced comment on active_mmu_pages
  KVM: Documentation: rectify rst markup in kvm_run-&gt;flags
  Documentation: kvm: fix messy conversion from .txt to .rst
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: x86/xen: Add support for vCPU runstate information</title>
<updated>2021-03-02T19:30:54+00:00</updated>
<author>
<name>David Woodhouse</name>
<email>dwmw@amazon.co.uk</email>
</author>
<published>2021-03-01T12:53:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=30b5c851af7991ad08abe90c1e7c31615fa98a1a'/>
<id>30b5c851af7991ad08abe90c1e7c31615fa98a1a</id>
<content type='text'>
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 &lt;joao.m.martins@oracle.com&gt;
Signed-off-by: Joao Martins &lt;joao.m.martins@oracle.com&gt;
Signed-off-by: David Woodhouse &lt;dwmw@amazon.co.uk&gt;
Message-Id: &lt;20210301125309.874953-2-dwmw2@infradead.org&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 &lt;joao.m.martins@oracle.com&gt;
Signed-off-by: Joao Martins &lt;joao.m.martins@oracle.com&gt;
Signed-off-by: David Woodhouse &lt;dwmw@amazon.co.uk&gt;
Message-Id: &lt;20210301125309.874953-2-dwmw2@infradead.org&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: Documentation: Fix index for KVM_CAP_PPC_DAWR1</title>
<updated>2021-03-02T19:30:53+00:00</updated>
<author>
<name>Kai Huang</name>
<email>kai.huang@intel.com</email>
</author>
<published>2021-02-26T09:48:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7d2cdad0da9dc0b1eb74c498c155be8c35a49ee6'/>
<id>7d2cdad0da9dc0b1eb74c498c155be8c35a49ee6</id>
<content type='text'>
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 &lt;kai.huang@intel.com&gt;
Message-Id: &lt;20210226094832.380394-1-kai.huang@intel.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 &lt;kai.huang@intel.com&gt;
Message-Id: &lt;20210226094832.380394-1-kai.huang@intel.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm</title>
<updated>2021-02-26T18:00:12+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-02-26T18:00:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d94d14008efed91a6de5de03627e0cdadb32c588'/>
<id>d94d14008efed91a6de5de03627e0cdadb32c588</id>
<content type='text'>
Pull more KVM updates from Paolo Bonzini:
 "x86:

   - take into account HVA before retrying on MMU notifier race

   - fixes for nested AMD guests without NPT

   - allow INVPCID in guest without PCID

   - disable PML in hardware when not in use

   - MMU code cleanups:

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (28 commits)
  KVM: SVM: Fix nested VM-Exit on #GP interception handling
  KVM: vmx/pmu: Fix dummy check if lbr_desc-&gt;event is created
  KVM: x86/mmu: Consider the hva in mmu_notifier retry
  KVM: x86/mmu: Skip mmu_notifier check when handling MMIO page fault
  KVM: Documentation: rectify rst markup in KVM_GET_SUPPORTED_HV_CPUID
  KVM: nSVM: prepare guest save area while is_guest_mode is true
  KVM: x86/mmu: Remove a variety of unnecessary exports
  KVM: x86: Fold "write-protect large" use case into generic write-protect
  KVM: x86/mmu: Don't set dirty bits when disabling dirty logging w/ PML
  KVM: VMX: Dynamically enable/disable PML based on memslot dirty logging
  KVM: x86: Further clarify the logic and comments for toggling log dirty
  KVM: x86: Move MMU's PML logic to common code
  KVM: x86/mmu: Make dirty log size hook (PML) a value, not a function
  KVM: x86/mmu: Expand on the comment in kvm_vcpu_ad_need_write_protect()
  KVM: nVMX: Disable PML in hardware when running L2
  KVM: x86/mmu: Consult max mapping level when zapping collapsible SPTEs
  KVM: x86/mmu: Pass the memslot to the rmap callbacks
  KVM: x86/mmu: Split out max mapping level calculation to helper
  KVM: x86/mmu: Expand collapsible SPTE zap for TDP MMU to ZONE_DEVICE and HugeTLB pages
  KVM: nVMX: no need to undo inject_page_fault change on nested vmexit
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull more KVM updates from Paolo Bonzini:
 "x86:

   - take into account HVA before retrying on MMU notifier race

   - fixes for nested AMD guests without NPT

   - allow INVPCID in guest without PCID

   - disable PML in hardware when not in use

   - MMU code cleanups:

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (28 commits)
  KVM: SVM: Fix nested VM-Exit on #GP interception handling
  KVM: vmx/pmu: Fix dummy check if lbr_desc-&gt;event is created
  KVM: x86/mmu: Consider the hva in mmu_notifier retry
  KVM: x86/mmu: Skip mmu_notifier check when handling MMIO page fault
  KVM: Documentation: rectify rst markup in KVM_GET_SUPPORTED_HV_CPUID
  KVM: nSVM: prepare guest save area while is_guest_mode is true
  KVM: x86/mmu: Remove a variety of unnecessary exports
  KVM: x86: Fold "write-protect large" use case into generic write-protect
  KVM: x86/mmu: Don't set dirty bits when disabling dirty logging w/ PML
  KVM: VMX: Dynamically enable/disable PML based on memslot dirty logging
  KVM: x86: Further clarify the logic and comments for toggling log dirty
  KVM: x86: Move MMU's PML logic to common code
  KVM: x86/mmu: Make dirty log size hook (PML) a value, not a function
  KVM: x86/mmu: Expand on the comment in kvm_vcpu_ad_need_write_protect()
  KVM: nVMX: Disable PML in hardware when running L2
  KVM: x86/mmu: Consult max mapping level when zapping collapsible SPTEs
  KVM: x86/mmu: Pass the memslot to the rmap callbacks
  KVM: x86/mmu: Split out max mapping level calculation to helper
  KVM: x86/mmu: Expand collapsible SPTE zap for TDP MMU to ZONE_DEVICE and HugeTLB pages
  KVM: nVMX: no need to undo inject_page_fault change on nested vmexit
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: Documentation: rectify rst markup in kvm_run-&gt;flags</title>
<updated>2021-02-26T08:03:12+00:00</updated>
<author>
<name>Chenyi Qiang</name>
<email>chenyi.qiang@intel.com</email>
</author>
<published>2021-02-26T07:55:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=96564d777366417cca0f5b39fc13202a1d7d9881'/>
<id>96564d777366417cca0f5b39fc13202a1d7d9881</id>
<content type='text'>
Commit c32b1b896d2a ("KVM: X86: Add the Document for
KVM_CAP_X86_BUS_LOCK_EXIT") added a new flag in kvm_run-&gt;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 &lt;chenyi.qiang@intel.com&gt;
Message-Id: &lt;20210226075541.27179-1-chenyi.qiang@intel.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit c32b1b896d2a ("KVM: X86: Add the Document for
KVM_CAP_X86_BUS_LOCK_EXIT") added a new flag in kvm_run-&gt;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 &lt;chenyi.qiang@intel.com&gt;
Message-Id: &lt;20210226075541.27179-1-chenyi.qiang@intel.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
