From: Yuan Yao <yuan.yao@linux.intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Marc Zyngier <maz@kernel.org>,
Huacai Chen <chenhuacai@kernel.org>,
Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
Anup Patel <anup@brainfault.org>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Janosch Frank <frankja@linux.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
Matthew Rosato <mjrosato@linux.ibm.com>,
Eric Farman <farman@linux.ibm.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Oliver Upton <oliver.upton@linux.dev>,
Atish Patra <atishp@atishpatra.org>,
David Hildenbrand <david@redhat.com>,
kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
kvmarm@lists.linux.dev, kvmarm@lists.cs.columbia.edu,
linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
Isaku Yamahata <isaku.yamahata@intel.com>,
Fabiano Rosas <farosas@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Chao Gao <chao.gao@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Yuan Yao <yuan.yao@intel.com>
Subject: Re: [PATCH 08/44] KVM: x86: Move hardware setup/unsetup to init/exit
Date: Fri, 4 Nov 2022 14:22:23 +0800 [thread overview]
Message-ID: <20221104062223.7kcrbt66mlmqxk7f@yy-desk-7060> (raw)
In-Reply-To: <20221102231911.3107438-9-seanjc@google.com>
On Wed, Nov 02, 2022 at 11:18:35PM +0000, Sean Christopherson wrote:
> Now that kvm_arch_hardware_setup() is called immediately after
> kvm_arch_init(), fold the guts of kvm_arch_hardware_(un)setup() into
> kvm_arch_{init,exit}() as a step towards dropping one of the hooks.
>
> To avoid having to unwind various setup, e.g registration of several
> notifiers, slot in the vendor hardware setup before the registration of
> said notifiers and callbacks. Introducing a functional change while
> moving code is less than ideal, but the alternative is adding a pile of
> unwinding code, which is much more error prone, e.g. several attempts to
> move the setup code verbatim all introduced bugs.
>
> Add a comment to document that kvm_ops_update() is effectively the point
> of no return, e.g. it sets the kvm_x86_ops.hardware_enable canary and so
> needs to be unwound.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> arch/x86/kvm/x86.c | 121 +++++++++++++++++++++++----------------------
> 1 file changed, 63 insertions(+), 58 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 9a7702b1c563..80ee580a9cd4 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -9252,6 +9252,24 @@ static struct notifier_block pvclock_gtod_notifier = {
> };
> #endif
>
> +static inline void kvm_ops_update(struct kvm_x86_init_ops *ops)
> +{
> + memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));
> +
> +#define __KVM_X86_OP(func) \
> + static_call_update(kvm_x86_##func, kvm_x86_ops.func);
> +#define KVM_X86_OP(func) \
> + WARN_ON(!kvm_x86_ops.func); __KVM_X86_OP(func)
> +#define KVM_X86_OP_OPTIONAL __KVM_X86_OP
> +#define KVM_X86_OP_OPTIONAL_RET0(func) \
> + static_call_update(kvm_x86_##func, (void *)kvm_x86_ops.func ? : \
> + (void *)__static_call_return0);
> +#include <asm/kvm-x86-ops.h>
> +#undef __KVM_X86_OP
> +
> + kvm_pmu_ops_update(ops->pmu_ops);
> +}
> +
> int kvm_arch_init(void *opaque)
> {
> struct kvm_x86_init_ops *ops = opaque;
> @@ -9325,6 +9343,24 @@ int kvm_arch_init(void *opaque)
> kvm_caps.supported_xcr0 = host_xcr0 & KVM_SUPPORTED_XCR0;
> }
>
> + rdmsrl_safe(MSR_EFER, &host_efer);
> +
> + if (boot_cpu_has(X86_FEATURE_XSAVES))
> + rdmsrl(MSR_IA32_XSS, host_xss);
> +
> + kvm_init_pmu_capability();
> +
> + r = ops->hardware_setup();
> + if (r != 0)
> + goto out_mmu_exit;
The failure case of ops->hardware_setup() is unwound
by kvm_arch_exit() before this patch, do we need to
keep that old behavior ?
> +
> + /*
> + * Point of no return! DO NOT add error paths below this point unless
> + * absolutely necessary, as most operations from this point forward
> + * require unwinding.
> + */
> + kvm_ops_update(ops);
> +
> kvm_timer_init();
>
> if (pi_inject_timer == -1)
> @@ -9336,8 +9372,32 @@ int kvm_arch_init(void *opaque)
> set_hv_tscchange_cb(kvm_hyperv_tsc_notifier);
> #endif
>
> + kvm_register_perf_callbacks(ops->handle_intel_pt_intr);
> +
> + if (!kvm_cpu_cap_has(X86_FEATURE_XSAVES))
> + kvm_caps.supported_xss = 0;
> +
> +#define __kvm_cpu_cap_has(UNUSED_, f) kvm_cpu_cap_has(f)
> + cr4_reserved_bits = __cr4_reserved_bits(__kvm_cpu_cap_has, UNUSED_);
> +#undef __kvm_cpu_cap_has
> +
> + if (kvm_caps.has_tsc_control) {
> + /*
> + * Make sure the user can only configure tsc_khz values that
> + * fit into a signed integer.
> + * A min value is not calculated because it will always
> + * be 1 on all machines.
> + */
> + u64 max = min(0x7fffffffULL,
> + __scale_tsc(kvm_caps.max_tsc_scaling_ratio, tsc_khz));
> + kvm_caps.max_guest_tsc_khz = max;
> + }
> + kvm_caps.default_tsc_scaling_ratio = 1ULL << kvm_caps.tsc_scaling_ratio_frac_bits;
> + kvm_init_msr_list();
> return 0;
>
> +out_mmu_exit:
> + kvm_mmu_vendor_module_exit();
> out_free_percpu:
> free_percpu(user_return_msrs);
> out_free_x86_emulator_cache:
> @@ -9347,6 +9407,8 @@ int kvm_arch_init(void *opaque)
>
> void kvm_arch_exit(void)
> {
> + kvm_unregister_perf_callbacks();
> +
> #ifdef CONFIG_X86_64
> if (hypervisor_is_type(X86_HYPER_MS_HYPERV))
> clear_hv_tscchange_cb();
> @@ -9362,6 +9424,7 @@ void kvm_arch_exit(void)
> irq_work_sync(&pvclock_irq_work);
> cancel_work_sync(&pvclock_gtod_work);
> #endif
> + static_call(kvm_x86_hardware_unsetup)();
> kvm_x86_ops.hardware_enable = NULL;
> kvm_mmu_vendor_module_exit();
> free_percpu(user_return_msrs);
> @@ -11922,72 +11985,14 @@ void kvm_arch_hardware_disable(void)
> drop_user_return_notifiers();
> }
>
> -static inline void kvm_ops_update(struct kvm_x86_init_ops *ops)
> -{
> - memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));
> -
> -#define __KVM_X86_OP(func) \
> - static_call_update(kvm_x86_##func, kvm_x86_ops.func);
> -#define KVM_X86_OP(func) \
> - WARN_ON(!kvm_x86_ops.func); __KVM_X86_OP(func)
> -#define KVM_X86_OP_OPTIONAL __KVM_X86_OP
> -#define KVM_X86_OP_OPTIONAL_RET0(func) \
> - static_call_update(kvm_x86_##func, (void *)kvm_x86_ops.func ? : \
> - (void *)__static_call_return0);
> -#include <asm/kvm-x86-ops.h>
> -#undef __KVM_X86_OP
> -
> - kvm_pmu_ops_update(ops->pmu_ops);
> -}
> -
> int kvm_arch_hardware_setup(void *opaque)
> {
> - struct kvm_x86_init_ops *ops = opaque;
> - int r;
> -
> - rdmsrl_safe(MSR_EFER, &host_efer);
> -
> - if (boot_cpu_has(X86_FEATURE_XSAVES))
> - rdmsrl(MSR_IA32_XSS, host_xss);
> -
> - kvm_init_pmu_capability();
> -
> - r = ops->hardware_setup();
> - if (r != 0)
> - return r;
> -
> - kvm_ops_update(ops);
> -
> - kvm_register_perf_callbacks(ops->handle_intel_pt_intr);
> -
> - if (!kvm_cpu_cap_has(X86_FEATURE_XSAVES))
> - kvm_caps.supported_xss = 0;
> -
> -#define __kvm_cpu_cap_has(UNUSED_, f) kvm_cpu_cap_has(f)
> - cr4_reserved_bits = __cr4_reserved_bits(__kvm_cpu_cap_has, UNUSED_);
> -#undef __kvm_cpu_cap_has
> -
> - if (kvm_caps.has_tsc_control) {
> - /*
> - * Make sure the user can only configure tsc_khz values that
> - * fit into a signed integer.
> - * A min value is not calculated because it will always
> - * be 1 on all machines.
> - */
> - u64 max = min(0x7fffffffULL,
> - __scale_tsc(kvm_caps.max_tsc_scaling_ratio, tsc_khz));
> - kvm_caps.max_guest_tsc_khz = max;
> - }
> - kvm_caps.default_tsc_scaling_ratio = 1ULL << kvm_caps.tsc_scaling_ratio_frac_bits;
> - kvm_init_msr_list();
> return 0;
> }
>
> void kvm_arch_hardware_unsetup(void)
> {
> - kvm_unregister_perf_callbacks();
>
> - static_call(kvm_x86_hardware_unsetup)();
> }
>
> int kvm_arch_check_processor_compat(void *opaque)
> --
> 2.38.1.431.g37b22c650d-goog
>
next prev parent reply other threads:[~2022-11-04 6:23 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-02 23:18 [PATCH 00/44] KVM: Rework kvm_init() and hardware enabling Sean Christopherson
2022-11-02 23:18 ` [PATCH 01/44] KVM: Register /dev/kvm as the _very_ last thing during initialization Sean Christopherson
2022-11-02 23:18 ` [PATCH 02/44] KVM: Initialize IRQ FD after arch hardware setup Sean Christopherson
2022-11-04 0:41 ` Chao Gao
2022-11-04 20:15 ` Sean Christopherson
2022-11-02 23:18 ` [PATCH 03/44] KVM: Allocate cpus_hardware_enabled " Sean Christopherson
2022-11-04 5:37 ` Yuan Yao
2022-11-02 23:18 ` [PATCH 04/44] KVM: Teardown VFIO ops earlier in kvm_exit() Sean Christopherson
2022-11-03 12:46 ` Cornelia Huck
2022-11-07 17:56 ` Eric Farman
2022-11-02 23:18 ` [PATCH 05/44] KVM: s390: Unwind kvm_arch_init() piece-by-piece() if a step fails Sean Christopherson
2022-11-07 17:57 ` Eric Farman
2022-11-02 23:18 ` [PATCH 06/44] KVM: s390: Move hardware setup/unsetup to init/exit Sean Christopherson
2022-11-07 17:58 ` Eric Farman
2022-11-02 23:18 ` [PATCH 07/44] KVM: x86: Do timer initialization after XCR0 configuration Sean Christopherson
2022-11-02 23:18 ` [PATCH 08/44] KVM: x86: Move hardware setup/unsetup to init/exit Sean Christopherson
2022-11-04 6:22 ` Yuan Yao [this message]
2022-11-04 16:31 ` Sean Christopherson
2022-11-02 23:18 ` [PATCH 09/44] KVM: Drop arch hardware (un)setup hooks Sean Christopherson
2022-11-07 3:01 ` Anup Patel
2022-11-07 18:22 ` Eric Farman
2022-11-02 23:18 ` [PATCH 10/44] KVM: VMX: Clean up eVMCS enabling if KVM initialization fails Sean Christopherson
2022-11-03 14:01 ` Paolo Bonzini
2022-11-03 14:04 ` Paolo Bonzini
2022-11-03 14:28 ` Vitaly Kuznetsov
2022-11-11 1:38 ` Sean Christopherson
2022-11-15 9:30 ` Vitaly Kuznetsov
2022-11-02 23:18 ` [PATCH 11/44] KVM: x86: Move guts of kvm_arch_init() to standalone helper Sean Christopherson
2022-11-02 23:18 ` [PATCH 12/44] KVM: VMX: Do _all_ initialization before exposing /dev/kvm to userspace Sean Christopherson
2022-11-02 23:18 ` [PATCH 13/44] KVM: x86: Serialize vendor module initialization (hardware setup) Sean Christopherson
2022-11-16 1:46 ` Huang, Kai
2022-11-16 15:52 ` Sean Christopherson
2022-11-02 23:18 ` [PATCH 14/44] KVM: arm64: Simplify the CPUHP logic Sean Christopherson
2022-11-02 23:18 ` [PATCH 15/44] KVM: arm64: Free hypervisor allocations if vector slot init fails Sean Christopherson
2022-11-02 23:18 ` [PATCH 16/44] KVM: arm64: Unregister perf callbacks if hypervisor finalization fails Sean Christopherson
2022-11-02 23:18 ` [PATCH 17/44] KVM: arm64: Do arm/arch initialiation without bouncing through kvm_init() Sean Christopherson
2022-11-03 7:25 ` Philippe Mathieu-Daudé
2022-11-03 15:29 ` Sean Christopherson
2022-11-02 23:18 ` [PATCH 18/44] KVM: arm64: Mark kvm_arm_init() and its unique descendants as __init Sean Christopherson
2022-11-02 23:18 ` [PATCH 19/44] KVM: MIPS: Hardcode callbacks to hardware virtualization extensions Sean Christopherson
2022-11-02 23:18 ` [PATCH 20/44] KVM: MIPS: Setup VZ emulation? directly from kvm_mips_init() Sean Christopherson
2022-11-03 7:10 ` Philippe Mathieu-Daudé
2022-11-02 23:18 ` [PATCH 21/44] KVM: MIPS: Register die notifier prior to kvm_init() Sean Christopherson
2022-11-03 7:12 ` Philippe Mathieu-Daudé
2022-11-02 23:18 ` [PATCH 22/44] KVM: RISC-V: Do arch init directly in riscv_kvm_init() Sean Christopherson
2022-11-03 7:14 ` Philippe Mathieu-Daudé
2022-11-07 3:05 ` Anup Patel
2022-11-02 23:18 ` [PATCH 23/44] KVM: RISC-V: Tag init functions and data with __init, __ro_after_init Sean Christopherson
2022-11-07 3:10 ` Anup Patel
2022-11-02 23:18 ` [PATCH 24/44] KVM: PPC: Move processor compatibility check to module init Sean Christopherson
2022-11-02 23:18 ` [PATCH 25/44] KVM: s390: Do s390 specific init without bouncing through kvm_init() Sean Christopherson
2022-11-03 7:16 ` Philippe Mathieu-Daudé
2022-11-03 12:44 ` Claudio Imbrenda
2022-11-03 13:21 ` Claudio Imbrenda
2022-11-07 18:22 ` Eric Farman
2022-11-02 23:18 ` [PATCH 26/44] KVM: s390: Mark __kvm_s390_init() and its descendants as __init Sean Christopherson
2022-11-07 18:22 ` Eric Farman
2022-11-02 23:18 ` [PATCH 27/44] KVM: Drop kvm_arch_{init,exit}() hooks Sean Christopherson
2022-11-03 7:18 ` Philippe Mathieu-Daudé
2022-11-07 3:13 ` Anup Patel
2022-11-07 19:08 ` Eric Farman
2022-11-02 23:18 ` [PATCH 28/44] KVM: VMX: Make VMCS configuration/capabilities structs read-only after init Sean Christopherson
2022-11-02 23:18 ` [PATCH 29/44] KVM: x86: Do CPU compatibility checks in x86 code Sean Christopherson
2022-11-02 23:18 ` [PATCH 30/44] KVM: Drop kvm_arch_check_processor_compat() hook Sean Christopherson
2022-11-03 7:20 ` Philippe Mathieu-Daudé
2022-11-07 3:16 ` Anup Patel
2022-11-07 19:08 ` Eric Farman
2022-11-02 23:18 ` [PATCH 31/44] KVM: x86: Use KBUILD_MODNAME to specify vendor module name Sean Christopherson
2022-11-02 23:18 ` [PATCH 32/44] KVM: x86: Unify pr_fmt to use module name for all KVM modules Sean Christopherson
2022-11-10 7:31 ` Robert Hoo
2022-11-10 16:50 ` Sean Christopherson
2022-11-30 23:02 ` Sean Christopherson
2022-12-01 1:34 ` Robert Hoo
2022-11-02 23:19 ` [PATCH 33/44] KVM: x86: Do VMX/SVM support checks directly in vendor code Sean Christopherson
2022-11-03 15:08 ` Paolo Bonzini
2022-11-03 18:35 ` Sean Christopherson
2022-11-03 18:46 ` Paolo Bonzini
2022-11-03 18:58 ` Sean Christopherson
2022-11-04 8:02 ` Paolo Bonzini
2022-11-04 15:40 ` Sean Christopherson
2022-11-15 22:50 ` Huang, Kai
2022-11-16 1:56 ` Sean Christopherson
2022-11-02 23:19 ` [PATCH 34/44] KVM: VMX: Shuffle support checks and hardware enabling code around Sean Christopherson
2022-11-02 23:19 ` [PATCH 35/44] KVM: SVM: Check for SVM support in CPU compatibility checks Sean Christopherson
2022-11-02 23:19 ` [PATCH 36/44] KVM: x86: Do compatibility checks when onlining CPU Sean Christopherson
2022-11-03 15:17 ` Paolo Bonzini
2022-11-03 17:44 ` Sean Christopherson
2022-11-03 17:57 ` Paolo Bonzini
2022-11-03 21:04 ` Isaku Yamahata
2022-11-03 22:34 ` Sean Christopherson
2022-11-04 7:18 ` Isaku Yamahata
2022-11-11 0:06 ` Sean Christopherson
2022-11-02 23:19 ` [PATCH 37/44] KVM: Rename and move CPUHP_AP_KVM_STARTING to ONLINE section Sean Christopherson
2022-11-10 7:26 ` Robert Hoo
2022-11-10 16:49 ` Sean Christopherson
2022-11-02 23:19 ` [PATCH 38/44] KVM: Disable CPU hotplug during hardware enabling Sean Christopherson
2022-11-10 1:08 ` Huang, Kai
2022-11-10 2:20 ` Huang, Kai
2022-11-10 1:33 ` Huang, Kai
2022-11-10 2:11 ` Huang, Kai
2022-11-10 16:58 ` Sean Christopherson
2022-11-15 20:16 ` Sean Christopherson
2022-11-15 20:21 ` Sean Christopherson
2022-11-16 12:23 ` Huang, Kai
2022-11-16 17:11 ` Sean Christopherson
2022-11-17 1:39 ` Huang, Kai
2022-11-17 15:16 ` Sean Christopherson
2022-11-02 23:19 ` [PATCH 39/44] KVM: Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lock Sean Christopherson
2022-11-03 15:23 ` Paolo Bonzini
2022-11-03 17:53 ` Sean Christopherson
2022-11-02 23:19 ` [PATCH 40/44] KVM: Remove on_each_cpu(hardware_disable_nolock) in kvm_exit() Sean Christopherson
2022-11-02 23:19 ` [PATCH 41/44] KVM: Use a per-CPU variable to track which CPUs have enabled virtualization Sean Christopherson
2022-11-02 23:19 ` [PATCH 42/44] KVM: Make hardware_enable_failed a local variable in the "enable all" path Sean Christopherson
2022-11-02 23:19 ` [PATCH 43/44] KVM: Register syscore (suspend/resume) ops early in kvm_init() Sean Christopherson
2022-11-02 23:19 ` [PATCH 44/44] KVM: Opt out of generic hardware enabling on s390 and PPC Sean Christopherson
2022-11-07 3:23 ` Anup Patel
2022-11-03 12:08 ` [PATCH 00/44] KVM: Rework kvm_init() and hardware enabling Christian Borntraeger
2022-11-03 15:27 ` Paolo Bonzini
2022-11-04 7:17 ` Isaku Yamahata
2022-11-04 7:59 ` Paolo Bonzini
2022-11-04 20:27 ` Sean Christopherson
2022-11-07 21:46 ` Isaku Yamahata
2022-11-08 1:09 ` Huang, Kai
2022-11-08 5:43 ` Isaku Yamahata
2022-11-08 8:56 ` Huang, Kai
2022-11-08 10:35 ` Huang, Kai
2022-11-08 17:46 ` Sean Christopherson
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