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  1. Nov 11, 2021
    • David Woodhouse's avatar
      KVM: x86: Fix recording of guest steal time / preempted status · 7e2175eb
      David Woodhouse authored 
      In commit b0431382 ("x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is
not missed") we switched to using a gfn_to_pfn_cache for accessing the
guest steal time structure in order to allow for an atomic xchg of the
preempted field. This has a couple of problems.

Firstly, kvm_map_gfn() doesn't work at all for IOMEM pages when the
atomic flag is set, which it is in kvm_steal_time_set_preempted(). So a
guest vCPU using an IOMEM page for its steal time would never have its
preempted field set.

Secondly, the gfn_to_pfn_cache is not invalidated in all cases where it
should have been. There are two stages to the GFN->PFN conversion;
first the GFN is converted to a userspace HVA, and then that HVA is
looked up in the process page tables to find the underlying host PFN.
Correct invalidation of the latter would require being hooked up to the
MMU notifiers, but that doesn't happen---so it just keeps mapping and
unmapping the *wrong* PFN after the userspace page tables change.

In the !IOMEM case at least the stale page *is* pinned all the time it's
cached, so it won't be freed and reused by anyone else while still
receiving the steal time updates. The map/unmap dance only takes care
of the KVM administrivia such as marking the page dirty.

Until the gfn_to_pfn cache handles the remapping automatically by
integrating with the MMU notifiers, we might as well not get a
kernel mapping of it, and use the perfectly serviceable userspace HVA
that we already have.  We just need to implement the atomic xchg on
the userspace address with appropriate exception handling, which is
fairly trivial.

Cc: stable@vger.kernel.org
Fixes: b0431382

 ("x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is not missed")
Signed-off-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
Message-Id: <3645b9b889dac6438394194bb5586a46b68d581f.camel@infradead.org>
[I didn't entirely agree with David's assessment of the
 usefulness of the gfn_to_pfn cache, and integrated the outcome
 of the discussion in the above commit message. - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      7e2175eb
  3. Nov 02, 2021
  5. Nov 01, 2021
    • Bixuan Cui's avatar
      RISC-V: KVM: fix boolreturn.cocci warnings · bbd5ba8d
      Bixuan Cui authored 
      

Fix boolreturn.cocci warnings:
./arch/riscv/kvm/mmu.c:603:9-10: WARNING: return of 0/1 in function
'kvm_age_gfn' with return type bool
./arch/riscv/kvm/mmu.c:582:9-10: WARNING: return of 0/1 in function
'kvm_set_spte_gfn' with return type bool
./arch/riscv/kvm/mmu.c:621:9-10: WARNING: return of 0/1 in function
'kvm_test_age_gfn' with return type bool
./arch/riscv/kvm/mmu.c:568:9-10: WARNING: return of 0/1 in function
'kvm_unmap_gfn_range' with return type bool

Signed-off-by: default avatarBixuan Cui <cuibixuan@linux.alibaba.com>
Signed-off-by: default avatarAnup Patel <anup.patel@wdc.com>
      bbd5ba8d
    • ran jianping's avatar
      RISC-V: KVM: remove unneeded semicolon · 7b161d9c
      ran jianping authored 
      

 Elimate the following coccinelle check warning:
 ./arch/riscv/kvm/vcpu_sbi.c:169:2-3: Unneeded semicolon
 ./arch/riscv/kvm/vcpu_exit.c:397:2-3: Unneeded semicolon
 ./arch/riscv/kvm/vcpu_exit.c:687:2-3: Unneeded semicolon
 ./arch/riscv/kvm/vcpu_exit.c:645:2-3: Unneeded semicolon
 ./arch/riscv/kvm/vcpu.c:247:2-3: Unneeded semicolon
 ./arch/riscv/kvm/vcpu.c:284:2-3: Unneeded semicolon
 ./arch/riscv/kvm/vcpu_timer.c:123:2-3: Unneeded semicolon
 ./arch/riscv/kvm/vcpu_timer.c:170:2-3: Unneeded semicolon

Reported-by: default avatarZeal Robot <zealci@zte.com.cn>
Signed-off-by: default avatarran jianping <ran.jianping@zte.com.cn>
Signed-off-by: default avatarAnup Patel <anup.patel@wdc.com>
      7b161d9c
  7. Oct 31, 2021
    • Paolo Bonzini's avatar
      Merge tag 'kvm-s390-next-5.16-1' of... · 9c6eb531
      Paolo Bonzini authored 
      Merge tag 'kvm-s390-next-5.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

KVM: s390: Fixes and Features for 5.16

- SIGP Fixes
- initial preparations for lazy destroy of secure VMs
- storage key improvements/fixes
- Log the guest CPNC
      9c6eb531
    • Anup Patel's avatar
      RISC-V: KVM: Fix GPA passed to __kvm_riscv_hfence_gvma_xyz() functions · 7c8de080
      Anup Patel authored 
      The parameter passed to HFENCE.GVMA instruction in rs1 register
is guest physical address right shifted by 2 (i.e. divided by 4).

Unfortunately, we overlooked the semantics of rs1 registers for
HFENCE.GVMA instruction and never right shifted guest physical
address by 2. This issue did not manifest for hypervisors till
now because:
  1) Currently, only __kvm_riscv_hfence_gvma_all() and SBI
     HFENCE calls are used to invalidate TLB.
  2) All H-extension implementations (such as QEMU, Spike,
     Rocket Core FPGA, etc) that we tried till now were
     conservatively flushing everything upon any HFENCE.GVMA
     instruction.

This patch fixes GPA passed to __kvm_riscv_hfence_gvma_vmid_gpa()
and __kvm_riscv_hfence_gvma_gpa() functions.

Fixes: fd7bb4a2

 ("RISC-V: KVM: Implement VMID allocator")
Reported-by: default avatarIan Huang <ihuang@ventanamicro.com>
Signed-off-by: default avatarAnup Patel <anup.patel@wdc.com>
Message-Id: <20211026170136.2147619-4-anup.patel@wdc.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      7c8de080
    • Anup Patel's avatar
      RISC-V: KVM: Factor-out FP virtualization into separate sources · 0a86512d
      Anup Patel authored 
      

The timer and SBI virtualization is already in separate sources.
In future, we will have vector and AIA virtualization also added
as separate sources.

To align with above described modularity, we factor-out FP
virtualization into separate sources.

Signed-off-by: default avatarAnup Patel <anup.patel@wdc.com>
Message-Id: <20211026170136.2147619-3-anup.patel@wdc.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      0a86512d
    • Paolo Bonzini's avatar
      Merge tag 'kvmarm-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD · 4e338684
      Paolo Bonzini authored 
      KVM/arm64 updates for Linux 5.16

- More progress on the protected VM front, now with the full
  fixed feature set as well as the limitation of some hypercalls
  after initialisation.

- Cleanup of the RAZ/WI sysreg handling, which was pointlessly
  complicated

- Fixes for the vgic placement in the IPA space, together with a
  bunch of selftests

- More memcg accounting of the memory allocated on behalf of a guest

- Timer and vgic selftests

- Workarounds for the Apple M1 broken vgic implementation

- KConfig cleanups

- New kvmarm.mode=none option, for those who really dislike us
      4e338684
  9. Oct 27, 2021
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