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SubjectRe: [PATCH v2 00/45] KVM: Refactor vCPU creation
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Queued.  Paul, David, please test kvm/next in a couple days.

Paolo

On 18/12/19 22:54, Sean Christopherson wrote:
> The end goal of this series is to strip down the interface between common
> KVM code and arch specific code so that there is precisely one arch hook
> for creating a vCPU and one hook for destroying a vCPU. In addition to
> cleaning up the code base, simplifying the interface gives architectures
> more freedom to organize their vCPU creation code. Details below.
>
> v2:
> - Rebase to commit e41a90be9659 ("KVM: x86/mmu: WARN if root_hpa is
> invalid when handling a page fault"). A few minor x86 (VMX) conflicts,
> and one straightforward arm conflict with commit 8564d6372a7d ("KVM:
> arm64: Support stolen time reporting via shared structure") in patch
> "KVM: ARM: Move all vcpu init code into kvm_arch_vcpu_create()".
> - Collect Reviews and Acks [Christoffer, Greg].
> - Fix a warning in "KVM: arm64: Free sve_state via arm specific hook"
> by using a "void" return type [Christoffer].
> - Fix a bug in "KVM: PPC: Move kvm_vcpu_init() invocation to common code"
> where the call in kvmppc_core_vcpu_create_e500mc() was inadvertantly
> left behind.
>
>
> KVM's vCPU creation code is comically messy. kvm_vm_ioctl_create_vcpu()
> calls three separate arch hooks: init(), create() and setup(). The init()
> call is especially nasty as it's hidden away in a common KVM function,
> kvm_init_vcpu(), that for all intents and purposes must be immediately
> invoked after the vcpu object is allocated.
>
> Not to be outdone, vCPU destruction also has three arch hooks: uninit(),
> destroy() and free(), the latter of which isn't actually invoked by common
> KVM code, but the hook declaration still exists because architectures are
> relying on its forward declaration.
>
> Eliminating the extra arch hooks is relatively straightforward, just
> tedious. For the most part, there is no fundamental constraint that
> necessitated the proliferation of arch hooks, rather they crept in over
> time, usually when x86-centric code was moved out of generic KVM and into
> x86 code.
>
> E.g. kvm_arch_vcpu_setup() was added to allow x86 to do vcpu_load(), which
> can only be done after preempt_notifier initialization, but adding setup()
> overlooked the fact that the preempt_notifier was only initialized after
> kvm_arch_vcpu_create() because preemption support was added when x86's MMU
> setup (the vcpu_load() user) was called from common KVM code.
>
> For all intents and purposes, there is no true functional change in this
> series. The order of some allocations will change, and a few memory leaks
> are fixed, but the actual functionality of a guest should be unaffected.
>
> Patches 01-03 are bug fixes in error handling paths that were found by
> inspection when refactoring the associated code.
>
> Patches 04-43 refactor each arch implementation so that the unwanted arch
> hooks can be dropped without a functional change, e.g. move code out of
> kvm_arch_vcpu_setup() so that all implementations are empty, then drop the
> functions and caller.
>
> Patches 44-45 are minor clean up to eliminate kvm_vcpu_uninit().
>
> The net result is to go from this:
>
> vcpu = kvm_arch_vcpu_create(kvm, id);
> |
> |-> kvm_vcpu_init()
> |
> |-> kvm_arch_vcpu_init()
>
> if (IS_ERR(vcpu)) {
> r = PTR_ERR(vcpu);
> goto vcpu_decrement;
> }
>
> preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
>
> r = kvm_arch_vcpu_setup(vcpu);
> if (r)
> goto vcpu_destroy;
>
>
> Sean Christopherson (45):
> KVM: PPC: Book3S HV: Uninit vCPU if vcore creation fails
> KVM: PPC: Book3S PR: Free shared page if mmu initialization fails
> KVM: x86: Free wbinvd_dirty_mask if vCPU creation fails
> KVM: VMX: Allocate VPID after initializing VCPU
> KVM: VMX: Use direct vcpu pointer during vCPU create/free
> KVM: SVM: Use direct vcpu pointer during vCPU create/free
> KVM: x86: Allocate vcpu struct in common x86 code
> KVM: x86: Move FPU allocation to common x86 code
> KVM: x86: Move allocation of pio_data page down a few lines
> KVM: x86: Move kvm_vcpu_init() invocation to common code
> KVM: PPC: e500mc: Add build-time assert that vcpu is at offset 0
> KVM: PPC: Allocate vcpu struct in common PPC code
> KVM: PPC: Book3S PR: Allocate book3s and shadow vcpu after common init
> KVM: PPC: e500mc: Move reset of oldpir below call to kvm_vcpu_init()
> KVM: PPC: Move kvm_vcpu_init() invocation to common code
> KVM: MIPS: Use kvm_vcpu_cache to allocate vCPUs
> KVM: MIPS: Drop kvm_arch_vcpu_free()
> KVM: PPC: Drop kvm_arch_vcpu_free()
> KVM: arm: Drop kvm_arch_vcpu_free()
> KVM: x86: Remove spurious kvm_mmu_unload() from vcpu destruction path
> KVM: x86: Remove spurious clearing of async #PF MSR
> KVM: x86: Drop kvm_arch_vcpu_free()
> KVM: Remove kvm_arch_vcpu_free() declaration
> KVM: Add kvm_arch_vcpu_precreate() to handle pre-allocation issues
> KVM: s390: Move guts of kvm_arch_vcpu_init() into
> kvm_arch_vcpu_create()
> KVM: s390: Invoke kvm_vcpu_init() before allocating sie_page
> KVM: MIPS: Invoke kvm_vcpu_uninit() immediately prior to freeing vcpu
> KVM: x86: Invoke kvm_vcpu_uninit() immediately prior to freeing vcpu
> KVM: Introduce kvm_vcpu_destroy()
> KVM: Move vcpu alloc and init invocation to common code
> KVM: Unexport kvm_vcpu_cache and kvm_vcpu_{un}init()
> KVM: Move initialization of preempt notifier to kvm_vcpu_init()
> KVM: x86: Move guts of kvm_arch_vcpu_setup() into
> kvm_arch_vcpu_create()
> KVM: MIPS: Move .vcpu_setup() call to kvm_arch_vcpu_create()
> KVM: s390: Manually invoke vcpu setup during kvm_arch_vcpu_create()
> KVM: PPC: BookE: Setup vcpu during kvmppc_core_vcpu_create()
> KVM: Drop kvm_arch_vcpu_setup()
> KVM: x86: Move all vcpu init code into kvm_arch_vcpu_create()
> KVM: MIPS: Move all vcpu init code into kvm_arch_vcpu_create()
> KVM: ARM: Move all vcpu init code into kvm_arch_vcpu_create()
> KVM: PPC: Move all vcpu init code into kvm_arch_vcpu_create()
> KVM: arm64: Free sve_state via arm specific hook
> KVM: Drop kvm_arch_vcpu_init() and kvm_arch_vcpu_uninit()
> KVM: Move putting of vcpu->pid to kvm_vcpu_destroy()
> KVM: Move vcpu->run page allocation out of kvm_vcpu_init()
>
> arch/arm/include/asm/kvm_host.h | 2 +-
> arch/arm/kvm/guest.c | 5 -
> arch/arm64/include/asm/kvm_host.h | 2 +-
> arch/arm64/kvm/guest.c | 5 -
> arch/arm64/kvm/reset.c | 2 +-
> arch/mips/kvm/mips.c | 84 ++++-------
> arch/powerpc/include/asm/kvm_ppc.h | 6 +-
> arch/powerpc/kvm/book3s.c | 9 +-
> arch/powerpc/kvm/book3s_hv.c | 27 +---
> arch/powerpc/kvm/book3s_pr.c | 33 ++---
> arch/powerpc/kvm/booke.c | 65 ++++----
> arch/powerpc/kvm/e500.c | 34 +----
> arch/powerpc/kvm/e500mc.c | 28 +---
> arch/powerpc/kvm/powerpc.c | 70 ++++-----
> arch/s390/include/asm/kvm_host.h | 1 -
> arch/s390/kvm/kvm-s390.c | 110 +++++++-------
> arch/x86/include/asm/kvm_host.h | 2 +-
> arch/x86/kvm/svm.c | 52 +------
> arch/x86/kvm/vmx/vmx.c | 72 +++------
> arch/x86/kvm/x86.c | 230 ++++++++++++++---------------
> include/linux/kvm_host.h | 13 +-
> virt/kvm/arm/arm.c | 80 ++++------
> virt/kvm/kvm_main.c | 71 +++++----
> 23 files changed, 385 insertions(+), 618 deletions(-)
>

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