From: Gleb Natapov <[email protected]> Guest enables async PF vcpu functionality using this MSR.
Reviewed-by: Rik van Riel <[email protected]> Signed-off-by: Gleb Natapov <[email protected]> Signed-off-by: Marcelo Tosatti <[email protected]> diff --git a/Documentation/kvm/cpuid.txt b/Documentation/kvm/cpuid.txt index 14a12ea..8820685 100644 --- a/Documentation/kvm/cpuid.txt +++ b/Documentation/kvm/cpuid.txt @@ -36,6 +36,9 @@ KVM_FEATURE_MMU_OP || 2 || deprecated. KVM_FEATURE_CLOCKSOURCE2 || 3 || kvmclock available at msrs || || 0x4b564d00 and 0x4b564d01 ------------------------------------------------------------------------------ +KVM_FEATURE_ASYNC_PF || 4 || async pf can be enabled by + || || writing to msr 0x4b564d02 +------------------------------------------------------------------------------ KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side || || per-cpu warps are expected in || || kvmclock. diff --git a/Documentation/kvm/msr.txt b/Documentation/kvm/msr.txt index 8ddcfe8..27c11a6 100644 --- a/Documentation/kvm/msr.txt +++ b/Documentation/kvm/msr.txt @@ -3,7 +3,6 @@ Glauber Costa <[email protected]>, Red Hat Inc, 2010 ===================================================== KVM makes use of some custom MSRs to service some requests. -At present, this facility is only used by kvmclock. Custom MSRs have a range reserved for them, that goes from 0x4b564d00 to 0x4b564dff. There are MSRs outside this area, @@ -151,3 +150,38 @@ MSR_KVM_SYSTEM_TIME: 0x12 return PRESENT; } else return NON_PRESENT; + +MSR_KVM_ASYNC_PF_EN: 0x4b564d02 + data: Bits 63-6 hold 64-byte aligned physical address of a + 64 byte memory area which must be in guest RAM and must be + zeroed. Bits 5-1 are reserved and should be zero. Bit 0 is 1 + when asynchronous page faults are enabled on the vcpu 0 when + disabled. + + First 4 byte of 64 byte memory location will be written to by + the hypervisor at the time of asynchronous page fault (APF) + injection to indicate type of asynchronous page fault. Value + of 1 means that the page referred to by the page fault is not + present. Value 2 means that the page is now available. Disabling + interrupt inhibits APFs. Guest must not enable interrupt + before the reason is read, or it may be overwritten by another + APF. Since APF uses the same exception vector as regular page + fault guest must reset the reason to 0 before it does + something that can generate normal page fault. If during page + fault APF reason is 0 it means that this is regular page + fault. + + During delivery of type 1 APF cr2 contains a token that will + be used to notify a guest when missing page becomes + available. When page becomes available type 2 APF is sent with + cr2 set to the token associated with the page. There is special + kind of token 0xffffffff which tells vcpu that it should wake + up all processes waiting for APFs and no individual type 2 APFs + will be sent. + + If APF is disabled while there are outstanding APFs, they will + not be delivered. + + Currently type 2 APF will be always delivered on the same vcpu as + type 1 was, but guest should not rely on that. + diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 96aca44..26b2064 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -419,6 +419,8 @@ struct kvm_vcpu_arch { struct { bool halted; gfn_t gfns[roundup_pow_of_two(ASYNC_PF_PER_VCPU)]; + struct gfn_to_hva_cache data; + u64 msr_val; } apf; }; diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h index e3faaaf..8662ae0 100644 --- a/arch/x86/include/asm/kvm_para.h +++ b/arch/x86/include/asm/kvm_para.h @@ -20,6 +20,7 @@ * are available. The use of 0x11 and 0x12 is deprecated */ #define KVM_FEATURE_CLOCKSOURCE2 3 +#define KVM_FEATURE_ASYNC_PF 4 /* The last 8 bits are used to indicate how to interpret the flags field * in pvclock structure. If no bits are set, all flags are ignored. @@ -32,9 +33,12 @@ /* Custom MSRs falls in the range 0x4b564d00-0x4b564dff */ #define MSR_KVM_WALL_CLOCK_NEW 0x4b564d00 #define MSR_KVM_SYSTEM_TIME_NEW 0x4b564d01 +#define MSR_KVM_ASYNC_PF_EN 0x4b564d02 #define KVM_MAX_MMU_OP_BATCH 32 +#define KVM_ASYNC_PF_ENABLED (1 << 0) + /* Operations for KVM_HC_MMU_OP */ #define KVM_MMU_OP_WRITE_PTE 1 #define KVM_MMU_OP_FLUSH_TLB 2 diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index bcc48bc..4013b9b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -788,12 +788,12 @@ EXPORT_SYMBOL_GPL(kvm_get_dr); * kvm-specific. Those are put in the beginning of the list. */ -#define KVM_SAVE_MSRS_BEGIN 7 +#define KVM_SAVE_MSRS_BEGIN 8 static u32 msrs_to_save[] = { MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK, MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW, HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL, - HV_X64_MSR_APIC_ASSIST_PAGE, + HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP, MSR_STAR, #ifdef CONFIG_X86_64 @@ -1430,6 +1430,29 @@ static int set_msr_hyperv(struct kvm_vcpu *vcpu, u32 msr, u64 data) return 0; } +static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data) +{ + gpa_t gpa = data & ~0x3f; + + /* Bits 1:5 are resrved, Should be zero */ + if (data & 0x3e) + return 1; + + vcpu->arch.apf.msr_val = data; + + if (!(data & KVM_ASYNC_PF_ENABLED)) { + kvm_clear_async_pf_completion_queue(vcpu); + kvm_async_pf_hash_reset(vcpu); + return 0; + } + + if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.apf.data, gpa)) + return 1; + + kvm_async_pf_wakeup_all(vcpu); + return 0; +} + int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) { switch (msr) { @@ -1511,6 +1534,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) } break; } + case MSR_KVM_ASYNC_PF_EN: + if (kvm_pv_enable_async_pf(vcpu, data)) + return 1; + break; case MSR_IA32_MCG_CTL: case MSR_IA32_MCG_STATUS: case MSR_IA32_MC0_CTL ... MSR_IA32_MC0_CTL + 4 * KVM_MAX_MCE_BANKS - 1: @@ -1787,6 +1814,9 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) case MSR_KVM_SYSTEM_TIME_NEW: data = vcpu->arch.time; break; + case MSR_KVM_ASYNC_PF_EN: + data = vcpu->arch.apf.msr_val; + break; case MSR_IA32_P5_MC_ADDR: case MSR_IA32_P5_MC_TYPE: case MSR_IA32_MCG_CAP: @@ -1934,6 +1964,7 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_DEBUGREGS: case KVM_CAP_X86_ROBUST_SINGLESTEP: case KVM_CAP_XSAVE: + case KVM_CAP_ASYNC_PF: r = 1; break; case KVM_CAP_COALESCED_MMIO: @@ -5784,6 +5815,8 @@ free_vcpu: void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) { + vcpu->arch.apf.msr_val = 0; + vcpu_load(vcpu); kvm_mmu_unload(vcpu); vcpu_put(vcpu); @@ -5803,6 +5836,7 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu) vcpu->arch.dr7 = DR7_FIXED_1; kvm_make_request(KVM_REQ_EVENT, vcpu); + vcpu->arch.apf.msr_val = 0; kvm_clear_async_pf_completion_queue(vcpu); kvm_async_pf_hash_reset(vcpu); diff --git a/include/linux/kvm.h b/include/linux/kvm.h index 919ae53..ea2dc1a 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -540,6 +540,7 @@ struct kvm_ppc_pvinfo { #endif #define KVM_CAP_PPC_GET_PVINFO 57 #define KVM_CAP_PPC_IRQ_LEVEL 58 +#define KVM_CAP_ASYNC_PF 59 #ifdef KVM_CAP_IRQ_ROUTING diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index dda88f2..5d09197 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -93,6 +93,7 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu); void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu); int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, struct kvm_arch_async_pf *arch); +int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); #endif struct kvm_vcpu { diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index e97eae9..1f59498 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -190,3 +190,23 @@ retry_sync: kmem_cache_free(async_pf_cache, work); return 0; } + +int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) +{ + struct kvm_async_pf *work; + + if (!list_empty(&vcpu->async_pf.done)) + return 0; + + work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); + if (!work) + return -ENOMEM; + + work->page = bad_page; + get_page(bad_page); + INIT_LIST_HEAD(&work->queue); /* for list_del to work */ + + list_add_tail(&work->link, &vcpu->async_pf.done); + vcpu->async_pf.queued++; + return 0; +} -- To unsubscribe from this list: send the line "unsubscribe kvm-commits" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
