kernel/linux.git/arch/powerpc/kvm, branch v6.6.151

KVM: Introduce vcpu->wants_to_run

2026-08-03T09:15:40+00:00

[ Upstream commit a6816314af5749cd88944bfdceb270c627cdf348 ] Introduce vcpu->wants_to_run to indicate when a vCPU is in its core run loop, i.e. when the vCPU is running the KVM_RUN ioctl and immediate_exit was not set. Replace all references to vcpu->run->immediate_exit with !vcpu->wants_to_run to avoid TOCTOU races with userspace. For example, a malicious userspace could invoked KVM_RUN with immediate_exit=true and then after KVM reads it to set wants_to_run=false, flip it to false. This would result in the vCPU running in KVM_RUN with wants_to_run=false. This wouldn't cause any real bugs today but is a dangerous landmine. Signed-off-by: David Matlack Link: https://lore.kernel.org/r/20240503181734.1467938-2-dmatlack@google.com Signed-off-by: Sean Christopherson Stable-dep-of: e800decd9c0a ("KVM: x86: Only reset TSC Deadline Timer in apic_timer_expired on KVM_RUN") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

Revert "KVM: PPC: e500: Mark "struct page" dirty in kvmppc_e500_shadow_map()"

2025-03-13T11:58:39+00:00

This reverts commit 15d60c13b704f770ba45c58477380d4577cebfa3 which is commit c9be85dabb376299504e0d391d15662c0edf8273 upstream. It should not have been applied. Link: https://lore.kernel.org/r/CABgObfb5U9zwTQBPkPB=mKu-vMrRspPCm4wfxoQpB+SyAnb5WQ@mail.gmail.com Reported-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

Revert "KVM: PPC: e500: Mark "struct page" pfn accessed before dropping mmu_lock"

2025-03-13T11:58:39+00:00

This reverts commit 59e21c4613b0a46f46eb124984928df46d88ad57 which is commit 84cf78dcd9d65c45ab73998d4ad50f433d53fb93 upstream. It should not have been applied. Link: https://lore.kernel.org/r/CABgObfb5U9zwTQBPkPB=mKu-vMrRspPCm4wfxoQpB+SyAnb5WQ@mail.gmail.com Reported-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

Revert "KVM: PPC: e500: Use __kvm_faultin_pfn() to handle page faults"

2025-03-13T11:58:39+00:00

This reverts commit ba3cf83f4a5063edb6ee150633e641954ce30478 which is commit 419cfb983ca93e75e905794521afefcfa07988bb upstream. It should not have been applied. Link: https://lore.kernel.org/r/CABgObfb5U9zwTQBPkPB=mKu-vMrRspPCm4wfxoQpB+SyAnb5WQ@mail.gmail.com Reported-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

Revert "KVM: e500: always restore irqs"

2025-03-13T11:58:39+00:00

This reverts commit b9d93eda1214985d1b3d00a0f9d4306282a5b189 which is commit 87ecfdbc699cc95fac73291b52650283ddcf929d upstream. It should not have been applied. Link: https://lore.kernel.org/r/CABgObfb5U9zwTQBPkPB=mKu-vMrRspPCm4wfxoQpB+SyAnb5WQ@mail.gmail.com Reported-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: e500: always restore irqs

2025-02-17T08:40:11+00:00

[ Upstream commit 87ecfdbc699cc95fac73291b52650283ddcf929d ] If find_linux_pte fails, IRQs will not be restored. This is unlikely to happen in practice since it would have been reported as hanging hosts, but it should of course be fixed anyway. Cc: stable@vger.kernel.org Reported-by: Sean Christopherson Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin

KVM: PPC: e500: Use __kvm_faultin_pfn() to handle page faults

2025-02-17T08:40:10+00:00

[ Upstream commit 419cfb983ca93e75e905794521afefcfa07988bb ] Convert PPC e500 to use __kvm_faultin_pfn()+kvm_release_faultin_page(), and continue the inexorable march towards the demise of kvm_pfn_to_refcounted_page(). Signed-off-by: Sean Christopherson Tested-by: Dmitry Osipenko Signed-off-by: Paolo Bonzini Message-ID: <20241010182427.1434605-55-seanjc@google.com> Stable-dep-of: 87ecfdbc699c ("KVM: e500: always restore irqs") Signed-off-by: Sasha Levin

KVM: PPC: e500: Mark "struct page" pfn accessed before dropping mmu_lock

2025-02-17T08:40:10+00:00

[ Upstream commit 84cf78dcd9d65c45ab73998d4ad50f433d53fb93 ] Mark pages accessed before dropping mmu_lock when faulting in guest memory so that shadow_map() can convert to kvm_release_faultin_page() without tripping its lockdep assertion on mmu_lock being held. Marking pages accessed outside of mmu_lock is ok (not great, but safe), but marking pages _dirty_ outside of mmu_lock can make filesystems unhappy. Signed-off-by: Sean Christopherson Tested-by: Dmitry Osipenko Signed-off-by: Paolo Bonzini Message-ID: <20241010182427.1434605-54-seanjc@google.com> Stable-dep-of: 87ecfdbc699c ("KVM: e500: always restore irqs") Signed-off-by: Sasha Levin

KVM: PPC: e500: Mark "struct page" dirty in kvmppc_e500_shadow_map()

2025-02-17T08:40:10+00:00

[ Upstream commit c9be85dabb376299504e0d391d15662c0edf8273 ] Mark the underlying page as dirty in kvmppc_e500_ref_setup()'s sole caller, kvmppc_e500_shadow_map(), which will allow converting e500 to __kvm_faultin_pfn() + kvm_release_faultin_page() without having to do a weird dance between ref_setup() and shadow_map(). Opportunistically drop the redundant kvm_set_pfn_accessed(), as shadow_map() puts the page via kvm_release_pfn_clean(). Signed-off-by: Sean Christopherson Tested-by: Dmitry Osipenko Signed-off-by: Paolo Bonzini Message-ID: <20241010182427.1434605-53-seanjc@google.com> Stable-dep-of: 87ecfdbc699c ("KVM: e500: always restore irqs") Signed-off-by: Sasha Levin

KVM: PPC: Book3S HV: Avoid returning to nested hypervisor on pending doorbells

2024-12-09T09:32:21+00:00

[ Upstream commit 26686db69917399fa30e3b3135360771e90f83ec ] Commit 6398326b9ba1 ("KVM: PPC: Book3S HV P9: Stop using vc->dpdes") dropped the use of vcore->dpdes for msgsndp / SMT emulation. Prior to that commit, the below code at L1 level (see [1] for terminology) was responsible for setting vc->dpdes for the respective L2 vCPU: if (!nested) { kvmppc_core_prepare_to_enter(vcpu); if (vcpu->arch.doorbell_request) { vc->dpdes = 1; smp_wmb(); vcpu->arch.doorbell_request = 0; } L1 then sent vc->dpdes to L0 via kvmhv_save_hv_regs(), and while servicing H_ENTER_NESTED at L0, the below condition at L0 level made sure to abort and go back to L1 if vcpu->arch.doorbell_request = 1 so that L1 sets vc->dpdes as per above if condition: } else if (vcpu->arch.pending_exceptions || vcpu->arch.doorbell_request || xive_interrupt_pending(vcpu)) { vcpu->arch.ret = RESUME_HOST; goto out; } This worked fine since vcpu->arch.doorbell_request was used more like a flag and vc->dpdes was used to pass around the doorbell state. But after Commit 6398326b9ba1 ("KVM: PPC: Book3S HV P9: Stop using vc->dpdes"), vcpu->arch.doorbell_request is the only variable used to pass around doorbell state. With the plumbing for handling doorbells for nested guests updated to use vcpu->arch.doorbell_request over vc->dpdes, the above "else if" stops doorbells from working correctly as L0 aborts execution of L2 and instead goes back to L1. Remove vcpu->arch.doorbell_request from the above "else if" condition as it is no longer needed for L0 to correctly handle the doorbell status while running L2. [1] Terminology 1. L0 : PowerNV linux running with HV privileges 2. L1 : Pseries KVM guest running on top of L0 2. L2 : Nested KVM guest running on top of L1 Fixes: 6398326b9ba1 ("KVM: PPC: Book3S HV P9: Stop using vc->dpdes") Signed-off-by: Gautam Menghani Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241109063301.105289-4-gautam@linux.ibm.com Signed-off-by: Sasha Levin