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Message-ID: <20240430193157.419425-1-seanjc@google.com> Date: Tue, 30 Apr 2024 12:31:53 -0700 From: Sean Christopherson <seanjc@...gle.com> To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, Tianrui Zhao <zhaotianrui@...ngson.cn>, Bibo Mao <maobibo@...ngson.cn>, Huacai Chen <chenhuacai@...nel.org>, Michael Ellerman <mpe@...erman.id.au>, Anup Patel <anup@...infault.org>, Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, Christian Borntraeger <borntraeger@...ux.ibm.com>, Janosch Frank <frankja@...ux.ibm.com>, Claudio Imbrenda <imbrenda@...ux.ibm.com>, Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com> Cc: linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev, kvm@...r.kernel.org, loongarch@...ts.linux.dev, linux-mips@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org, kvm-riscv@...ts.infradead.org, linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org Subject: [PATCH 0/4] KVM: Fold kvm_arch_sched_in() into kvm_arch_vcpu_load() Drop kvm_arch_sched_in() and instead pass a @sched_in boolean to kvm_arch_vcpu_load(). While fiddling with an idea for optimizing state management on AMD CPUs, I wanted to skip re-saving certain host state when a vCPU is scheduled back in, as the state (theoretically) shouldn't change for the task while it's scheduled out. Actually doing that was annoying and unnecessarily brittle due to having a separate API for the kvm_sched_in() case (the state save needed to be in kvm_arch_vcpu_load() for the common path). E.g. I could have set a "temporary"-ish flag somewhere in kvm_vcpu, but (a) that's gross and (b) it would rely on the arbitrary ordering between sched_in() and vcpu_load() staying the same. The only real downside I see is that arm64 and riscv end up having to pass "false" for their direct usage of kvm_arch_vcpu_load(), and passing boolean literals isn't ideal. But that can be solved by adding an inner helper that omits the @sched_in param (I almost added a patch to do that, but I couldn't convince myself it was necessary). The other motivation for this is to avoid yet another arch hook, and more arbitrary ordering, if there's a future need to hook kvm_sched_out() (we've come close on the x86 side several times). Sean Christopherson (4): KVM: Plumb in a @sched_in flag to kvm_arch_vcpu_load() KVM: VMX: Move PLE grow/shrink helpers above vmx_vcpu_load() KVM: x86: Fold kvm_arch_sched_in() into kvm_arch_vcpu_load() KVM: Delete the now unused kvm_arch_sched_in() arch/arm64/include/asm/kvm_host.h | 1 - arch/arm64/kvm/arm.c | 2 +- arch/arm64/kvm/emulate-nested.c | 4 +- arch/arm64/kvm/reset.c | 2 +- arch/loongarch/include/asm/kvm_host.h | 1 - arch/loongarch/kvm/vcpu.c | 2 +- arch/mips/include/asm/kvm_host.h | 1 - arch/mips/kvm/mmu.c | 2 +- arch/powerpc/include/asm/kvm_host.h | 1 - arch/powerpc/kvm/powerpc.c | 2 +- arch/riscv/include/asm/kvm_host.h | 1 - arch/riscv/kvm/vcpu.c | 4 +- arch/s390/include/asm/kvm_host.h | 1 - arch/s390/kvm/kvm-s390.c | 2 +- arch/x86/include/asm/kvm-x86-ops.h | 1 - arch/x86/include/asm/kvm_host.h | 4 +- arch/x86/kvm/pmu.c | 6 +-- arch/x86/kvm/svm/svm.c | 13 ++--- arch/x86/kvm/vmx/main.c | 2 - arch/x86/kvm/vmx/vmx.c | 75 +++++++++++++-------------- arch/x86/kvm/vmx/x86_ops.h | 3 +- arch/x86/kvm/x86.c | 26 +++++----- include/linux/kvm_host.h | 4 +- virt/kvm/kvm_main.c | 5 +- 24 files changed, 70 insertions(+), 95 deletions(-) base-commit: a96cb3bf390eebfead5fc7a2092f8452a7997d1b -- 2.45.0.rc0.197.gbae5840b3b-goog
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