From: Avi Kivity <avi@redhat.com> To: Gleb Natapov <gleb@redhat.com> Cc: kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mingo@elte.hu, a.p.zijlstra@chello.nl, tglx@linutronix.de, hpa@zytor.com, riel@redhat.com Subject: Re: [PATCH v2 02/12] Add PV MSR to enable asynchronous page faults delivery. Date: Wed, 25 Nov 2009 14:32:40 +0200 [thread overview] Message-ID: <4B0D23E8.3060508@redhat.com> (raw) In-Reply-To: <1258985167-29178-3-git-send-email-gleb@redhat.com> On 11/23/2009 04:05 PM, Gleb Natapov wrote: > Signed-off-by: Gleb Natapov<gleb@redhat.com> > --- > arch/x86/include/asm/kvm_host.h | 3 ++ > arch/x86/include/asm/kvm_para.h | 2 + > arch/x86/kvm/x86.c | 42 +++++++++++++++++++++++++++++++++++++- > include/linux/kvm.h | 1 + > 4 files changed, 46 insertions(+), 2 deletions(-) > > #define MSR_KVM_WALL_CLOCK 0x11 > #define MSR_KVM_SYSTEM_TIME 0x12 > +#define MSR_KVM_ASYNC_PF_EN 0x13 > Please use MSRs from the range 0x4b564dxx. The numbers below are reserved by Intel (and in fact used by the old Pentiums). Need documentation for the new MSR, say in Documentation/kvm/msr.txt. > +static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data) > +{ > + u64 gpa = data& ~0x3f; > + int offset = offset_in_page(gpa); > + unsigned long addr; > + > + addr = gfn_to_hva(vcpu->kvm, gpa>> PAGE_SHIFT); > + if (kvm_is_error_hva(addr)) > + return 1; > + > + vcpu->arch.apf_data = (u32 __user*)(addr + offset); > + > + /* check if address is mapped */ > + if (get_user(offset, vcpu->arch.apf_data)) { > + vcpu->arch.apf_data = NULL; > + return 1; > + } > What if the memory slot arrangement changes? This needs to be revalidated (and gfn_to_hva() called again). > + return 0; > +} > + > int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) > { > switch (msr) { > @@ -1029,6 +1049,14 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) > kvm_request_guest_time_update(vcpu); > break; > } > + case MSR_KVM_ASYNC_PF_EN: > + vcpu->arch.apf_msr_val = data; > + if (data& 1) { > + if (kvm_pv_enable_async_pf(vcpu, data)) > + return 1; > Need to check before setting the msr value, so subsequent reads return the old value. > + } else > + vcpu->arch.apf_data = NULL; > Need to check that bits 1:5 are zero. I think it's cleaner to move all of the code to kvm_pv_enable_async_pf(), to have everything in one place. -- error compiling committee.c: too many arguments to function
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com> To: Gleb Natapov <gleb@redhat.com> Cc: kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mingo@elte.hu, a.p.zijlstra@chello.nl, tglx@linutronix.de, hpa@zytor.com, riel@redhat.com Subject: Re: [PATCH v2 02/12] Add PV MSR to enable asynchronous page faults delivery. Date: Wed, 25 Nov 2009 14:32:40 +0200 [thread overview] Message-ID: <4B0D23E8.3060508@redhat.com> (raw) In-Reply-To: <1258985167-29178-3-git-send-email-gleb@redhat.com> On 11/23/2009 04:05 PM, Gleb Natapov wrote: > Signed-off-by: Gleb Natapov<gleb@redhat.com> > --- > arch/x86/include/asm/kvm_host.h | 3 ++ > arch/x86/include/asm/kvm_para.h | 2 + > arch/x86/kvm/x86.c | 42 +++++++++++++++++++++++++++++++++++++- > include/linux/kvm.h | 1 + > 4 files changed, 46 insertions(+), 2 deletions(-) > > #define MSR_KVM_WALL_CLOCK 0x11 > #define MSR_KVM_SYSTEM_TIME 0x12 > +#define MSR_KVM_ASYNC_PF_EN 0x13 > Please use MSRs from the range 0x4b564dxx. The numbers below are reserved by Intel (and in fact used by the old Pentiums). Need documentation for the new MSR, say in Documentation/kvm/msr.txt. > +static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data) > +{ > + u64 gpa = data& ~0x3f; > + int offset = offset_in_page(gpa); > + unsigned long addr; > + > + addr = gfn_to_hva(vcpu->kvm, gpa>> PAGE_SHIFT); > + if (kvm_is_error_hva(addr)) > + return 1; > + > + vcpu->arch.apf_data = (u32 __user*)(addr + offset); > + > + /* check if address is mapped */ > + if (get_user(offset, vcpu->arch.apf_data)) { > + vcpu->arch.apf_data = NULL; > + return 1; > + } > What if the memory slot arrangement changes? This needs to be revalidated (and gfn_to_hva() called again). > + return 0; > +} > + > int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) > { > switch (msr) { > @@ -1029,6 +1049,14 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) > kvm_request_guest_time_update(vcpu); > break; > } > + case MSR_KVM_ASYNC_PF_EN: > + vcpu->arch.apf_msr_val = data; > + if (data& 1) { > + if (kvm_pv_enable_async_pf(vcpu, data)) > + return 1; > Need to check before setting the msr value, so subsequent reads return the old value. > + } else > + vcpu->arch.apf_data = NULL; > Need to check that bits 1:5 are zero. I think it's cleaner to move all of the code to kvm_pv_enable_async_pf(), to have everything in one place. -- error compiling committee.c: too many arguments to function -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2009-11-25 12:32 UTC|newest] Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-11-23 14:05 [PATCH v2 00/12] KVM: Add asynchronous page fault for PV guest Gleb Natapov 2009-11-23 14:05 ` Gleb Natapov 2009-11-23 14:05 ` [PATCH v2 01/12] Move kvm_smp_prepare_boot_cpu() from kvmclock.c to kvm.c Gleb Natapov 2009-11-23 14:05 ` Gleb Natapov 2009-11-23 14:05 ` [PATCH v2 02/12] Add PV MSR to enable asynchronous page faults delivery Gleb Natapov 2009-11-23 14:05 ` Gleb Natapov 2009-11-25 12:32 ` Avi Kivity [this message] 2009-11-25 12:32 ` Avi Kivity 2009-11-23 14:05 ` [PATCH v2 03/12] Add async PF initialization to PV guest Gleb Natapov 2009-11-23 14:05 ` Gleb Natapov 2009-11-23 14:05 ` [PATCH v2 04/12] Add "handle page fault" PV helper Gleb Natapov 2009-11-23 14:05 ` Gleb Natapov 2009-11-23 15:32 ` Peter Zijlstra 2009-11-23 15:32 ` Peter Zijlstra 2009-11-23 15:32 ` Peter Zijlstra 2009-11-23 14:06 ` [PATCH v2 05/12] Handle asynchronous page fault in a PV guest Gleb Natapov 2009-11-23 14:06 ` Gleb Natapov 2009-11-25 12:45 ` Avi Kivity 2009-11-25 12:45 ` Avi Kivity 2009-11-23 14:06 ` [PATCH v2 06/12] Export __get_user_pages_fast Gleb Natapov 2009-11-23 14:06 ` Gleb Natapov 2009-11-23 14:06 ` [PATCH v2 07/12] Add get_user_pages() variant that fails if major fault is required Gleb Natapov 2009-11-23 14:06 ` Gleb Natapov 2009-11-23 14:06 ` [PATCH v2 08/12] Inject asynchronous page fault into a guest if page is swapped out Gleb Natapov 2009-11-23 14:06 ` Gleb Natapov 2009-11-25 13:03 ` Avi Kivity 2009-11-25 13:03 ` Avi Kivity 2009-11-23 14:06 ` [PATCH v2 09/12] Retry fault before vmentry Gleb Natapov 2009-11-23 14:06 ` Gleb Natapov 2009-11-25 13:09 ` Avi Kivity 2009-11-25 13:09 ` Avi Kivity 2009-11-25 13:20 ` Gleb Natapov 2009-11-25 13:20 ` Gleb Natapov 2009-11-23 14:06 ` [PATCH v2 10/12] Maintain preemptability count even for !CONFIG_PREEMPT kernels Gleb Natapov 2009-11-23 14:06 ` Gleb Natapov 2009-11-23 15:34 ` Peter Zijlstra 2009-11-23 15:34 ` Peter Zijlstra 2009-11-23 15:34 ` Peter Zijlstra 2009-11-23 15:58 ` Gleb Natapov 2009-11-23 15:58 ` Gleb Natapov 2009-11-23 17:30 ` Christoph Lameter 2009-11-23 17:30 ` Christoph Lameter 2009-11-24 7:12 ` Gleb Natapov 2009-11-24 7:12 ` Gleb Natapov 2009-11-24 15:14 ` Christoph Lameter 2009-11-24 15:14 ` Christoph Lameter 2009-11-30 10:56 ` Gleb Natapov 2009-11-30 10:56 ` Gleb Natapov 2009-11-30 10:58 ` Gleb Natapov 2009-11-30 10:58 ` Gleb Natapov 2009-11-30 10:59 ` Peter Zijlstra 2009-11-30 10:59 ` Peter Zijlstra 2009-11-30 10:59 ` Peter Zijlstra 2009-11-30 11:01 ` Avi Kivity 2009-11-30 11:01 ` Avi Kivity 2009-11-30 11:05 ` Peter Zijlstra 2009-11-30 11:05 ` Peter Zijlstra 2009-11-30 11:05 ` Peter Zijlstra 2009-11-30 16:23 ` Christoph Lameter 2009-11-30 16:23 ` Christoph Lameter 2009-11-23 14:06 ` [PATCH v2 11/12] Handle async PF in non preemptable context Gleb Natapov 2009-11-23 14:06 ` Gleb Natapov 2009-11-23 14:06 ` [PATCH v2 12/12] Send async PF when guest is not in userspace too Gleb Natapov 2009-11-23 14:06 ` Gleb Natapov
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