From: Sean Christopherson <seanjc@google.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Maxim Levitsky <mlevitsk@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Michael Kelley <mikelley@microsoft.com>,
Siddharth Chandrasekaran <sidcha@amazon.de>,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH v3 04/34] KVM: x86: hyper-v: Handle HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST{,EX} calls gently
Date: Wed, 18 May 2022 14:55:15 +0000 [thread overview]
Message-ID: <YoUI03NDdMPYTiSO@google.com> (raw)
In-Reply-To: <87y1yyucis.fsf@redhat.com>
On Wed, May 18, 2022, Vitaly Kuznetsov wrote:
> Sean Christopherson <seanjc@google.com> writes:
>
> > On Wed, May 18, 2022, Vitaly Kuznetsov wrote:
> >> Maxim Levitsky <mlevitsk@redhat.com> writes:
> >> > Or if using kfifo, then it can contain plain u64 items, which is even more natural.
> >> >
> >>
> >> In the next version I switch to fifo and get rid of 'flush_all' entries
> >> but instead of a boolean I use a 'magic' value of '-1' in GVA. This way
> >> we don't need to synchronize with the reader and add any special
> >> handling for the flag.
> >
> > Isn't -1 theoretically possible? Or is wrapping not allowed? E.g. requesting a
> > flush for address=0xfffffffffffff000, count = 0xfff will yield -1 and doesn't
> > create any illegal addresses in the process.
> >
>
> Such an error would just lead to KVM flushing the whole guest address
> space instead of flushing 4096 pages starting with 0xfffffffffffff000
> but over-flushing is always architecturally correct, isn't it?
Oh, duh. Yeah, flushing everything is totally ok. Maybe just add a comment above
the #define for the magic value calling out that corner case and why it's ok?
next prev parent reply other threads:[~2022-05-18 14:55 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-14 13:19 [PATCH v3 00/34] KVM: x86: hyper-v: Fine-grained TLB flush + L2 TLB flush feature Vitaly Kuznetsov
2022-04-14 13:19 ` [PATCH v3 01/34] KVM: x86: hyper-v: Resurrect dedicated KVM_REQ_HV_TLB_FLUSH flag Vitaly Kuznetsov
2022-05-11 11:18 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 02/34] KVM: x86: hyper-v: Introduce TLB flush ring Vitaly Kuznetsov
2022-05-11 11:19 ` Maxim Levitsky
2022-05-16 14:29 ` Vitaly Kuznetsov
2022-05-16 19:34 ` Sean Christopherson
2022-05-17 13:31 ` Vitaly Kuznetsov
2022-04-14 13:19 ` [PATCH v3 03/34] KVM: x86: hyper-v: Add helper to read hypercall data for array Vitaly Kuznetsov
2022-05-11 11:20 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 04/34] KVM: x86: hyper-v: Handle HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST{,EX} calls gently Vitaly Kuznetsov
2022-05-11 11:22 ` Maxim Levitsky
2022-05-18 9:39 ` Vitaly Kuznetsov
2022-05-18 14:18 ` Sean Christopherson
2022-05-18 14:43 ` Vitaly Kuznetsov
2022-05-18 14:55 ` Sean Christopherson [this message]
2022-05-16 19:41 ` Sean Christopherson
2022-05-17 13:41 ` Vitaly Kuznetsov
2022-04-14 13:19 ` [PATCH v3 05/34] KVM: x86: hyper-v: Expose support for extended gva ranges for flush hypercalls Vitaly Kuznetsov
2022-05-11 11:23 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 06/34] KVM: x86: Prepare kvm_hv_flush_tlb() to handle L2's GPAs Vitaly Kuznetsov
2022-05-11 11:23 ` Maxim Levitsky
2022-05-11 11:23 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 07/34] x86/hyperv: Introduce HV_MAX_SPARSE_VCPU_BANKS/HV_VCPUS_PER_SPARSE_BANK constants Vitaly Kuznetsov
2022-04-25 15:47 ` Wei Liu
2022-04-25 17:34 ` Michael Kelley (LINUX)
2022-04-25 19:09 ` Christophe JAILLET
2022-04-25 19:16 ` Christophe JAILLET
2022-05-03 14:59 ` Vitaly Kuznetsov
2022-05-03 11:11 ` Wei Liu
2022-05-11 11:23 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 08/34] KVM: x86: hyper-v: Use HV_MAX_SPARSE_VCPU_BANKS/HV_VCPUS_PER_SPARSE_BANK instead of raw '64' Vitaly Kuznetsov
2022-05-11 11:24 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 09/34] KVM: x86: hyper-v: Don't use sparse_set_to_vcpu_mask() in kvm_hv_send_ipi() Vitaly Kuznetsov
2022-05-11 11:24 ` Maxim Levitsky
2022-05-16 19:52 ` Sean Christopherson
2022-04-14 13:19 ` [PATCH v3 10/34] KVM: x86: hyper-v: Create a separate ring for L2 TLB flush Vitaly Kuznetsov
2022-05-11 11:24 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 11/34] KVM: x86: hyper-v: Use preallocated buffer in 'struct kvm_vcpu_hv' instead of on-stack 'sparse_banks' Vitaly Kuznetsov
2022-05-11 11:25 ` Maxim Levitsky
2022-05-16 20:05 ` Sean Christopherson
2022-05-17 13:51 ` Vitaly Kuznetsov
2022-05-17 14:04 ` Sean Christopherson
2022-05-17 14:19 ` Vitaly Kuznetsov
2022-04-14 13:19 ` [PATCH v3 12/34] KVM: nVMX: Keep track of hv_vm_id/hv_vp_id when eVMCS is in use Vitaly Kuznetsov
2022-05-11 11:25 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 13/34] KVM: nSVM: Keep track of Hyper-V hv_vm_id/hv_vp_id Vitaly Kuznetsov
2022-05-11 11:27 ` Maxim Levitsky
2022-05-18 12:25 ` Vitaly Kuznetsov
2022-05-18 12:45 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 14/34] KVM: x86: Introduce .post_hv_l2_tlb_flush() nested hook Vitaly Kuznetsov
2022-05-11 11:32 ` Maxim Levitsky
2022-05-18 12:43 ` Vitaly Kuznetsov
2022-05-18 12:49 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 15/34] KVM: x86: hyper-v: Introduce kvm_hv_is_tlb_flush_hcall() Vitaly Kuznetsov
2022-05-11 11:25 ` Maxim Levitsky
2022-05-16 20:09 ` Sean Christopherson
2022-04-14 13:19 ` [PATCH v3 16/34] KVM: x86: hyper-v: L2 TLB flush Vitaly Kuznetsov
2022-05-11 11:29 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 17/34] KVM: x86: hyper-v: Introduce fast kvm_hv_l2_tlb_flush_exposed() check Vitaly Kuznetsov
2022-05-11 11:30 ` Maxim Levitsky
2022-05-19 13:25 ` Vitaly Kuznetsov
2022-05-19 13:28 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 18/34] x86/hyperv: Fix 'struct hv_enlightened_vmcs' definition Vitaly Kuznetsov
2022-05-11 11:30 ` Maxim Levitsky
2022-04-14 13:19 ` [PATCH v3 19/34] KVM: nVMX: hyper-v: Enable L2 TLB flush Vitaly Kuznetsov
2022-05-11 11:31 ` Maxim Levitsky
2022-05-16 20:16 ` Sean Christopherson
2022-04-14 13:19 ` [PATCH v3 20/34] KVM: x86: KVM_REQ_TLB_FLUSH_CURRENT is a superset of KVM_REQ_HV_TLB_FLUSH too Vitaly Kuznetsov
2022-05-11 11:33 ` Maxim Levitsky
2022-05-19 9:12 ` Vitaly Kuznetsov
2022-05-19 23:44 ` Sean Christopherson
2022-04-14 13:20 ` [PATCH v3 21/34] KVM: nSVM: hyper-v: Enable L2 TLB flush Vitaly Kuznetsov
2022-05-11 11:33 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 22/34] KVM: x86: Expose Hyper-V L2 TLB flush feature Vitaly Kuznetsov
2022-05-11 11:34 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 23/34] KVM: selftests: Better XMM read/write helpers Vitaly Kuznetsov
2022-05-11 11:34 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 24/34] KVM: selftests: Hyper-V PV IPI selftest Vitaly Kuznetsov
2022-05-11 11:35 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 25/34] KVM: selftests: Make it possible to replace PTEs with __virt_pg_map() Vitaly Kuznetsov
2022-05-11 11:34 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 26/34] KVM: selftests: Hyper-V PV TLB flush selftest Vitaly Kuznetsov
2022-05-11 12:17 ` Maxim Levitsky
2022-05-24 14:51 ` Vitaly Kuznetsov
2022-04-14 13:20 ` [PATCH v3 27/34] KVM: selftests: Sync 'struct hv_enlightened_vmcs' definition with hyperv-tlfs.h Vitaly Kuznetsov
2022-05-11 12:17 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 28/34] KVM: selftests: nVMX: Allocate Hyper-V partition assist page Vitaly Kuznetsov
2022-05-11 12:17 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 29/34] KVM: selftests: nSVM: Allocate Hyper-V partition assist and VP assist pages Vitaly Kuznetsov
2022-05-11 12:17 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 30/34] KVM: selftests: Sync 'struct hv_vp_assist_page' definition with hyperv-tlfs.h Vitaly Kuznetsov
2022-05-11 12:18 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 31/34] KVM: selftests: evmcs_test: Introduce L2 TLB flush test Vitaly Kuznetsov
2022-05-11 12:18 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 32/34] KVM: selftests: Move Hyper-V VP assist page enablement out of evmcs.h Vitaly Kuznetsov
2022-05-11 12:18 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 33/34] KVM: selftests: hyperv_svm_test: Introduce L2 TLB flush test Vitaly Kuznetsov
2022-05-11 12:19 ` Maxim Levitsky
2022-04-14 13:20 ` [PATCH v3 34/34] KVM: x86: Rename 'enable_direct_tlbflush' to 'enable_l2_tlb_flush' Vitaly Kuznetsov
2022-05-11 12:18 ` Maxim Levitsky
2022-05-03 15:01 ` [PATCH v3 00/34] KVM: x86: hyper-v: Fine-grained TLB flush + L2 TLB flush feature Vitaly Kuznetsov
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