From: Paolo Bonzini <pbonzini@redhat.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
KarimAllah Ahmed <karahmed@amazon.de>
Cc: rkrcmar@redhat.com, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, jmattson@google.com
Subject: Re: [PATCH v4 00/14] KVM/X86: Introduce a new guest mapping interface
Date: Wed, 19 Dec 2018 22:27:28 +0100 [thread overview]
Message-ID: <3e43f0f6-9c24-fde1-38a5-456a0336de11@redhat.com> (raw)
In-Reply-To: <20181206160156.GB25299@char.us.oracle.com>
On 06/12/18 17:01, Konrad Rzeszutek Wilk wrote:
> On Mon, Dec 03, 2018 at 10:30:53AM +0100, KarimAllah Ahmed wrote:
>> Guest memory can either be directly managed by the kernel (i.e. have a "struct
>> page") or they can simply live outside kernel control (i.e. do not have a
>> "struct page"). KVM mostly support these two modes, except in a few places
>> where the code seems to assume that guest memory must have a "struct page".
>>
>> This patchset introduces a new mapping interface to map guest memory into host
>> kernel memory which also supports PFN-based memory (i.e. memory without 'struct
>> page'). It also converts all offending code to this interface or simply
>> read/write directly from guest memory.
>>
>> As far as I can see all offending code is now fixed except the APIC-access page
>> which I will handle in a seperate series along with dropping
>> kvm_vcpu_gfn_to_page and kvm_vcpu_gpa_to_page from the internal KVM API.
>>
>> The current implementation of the new API uses memremap to map memory that does
>> not have a "struct page". This proves to be very slow for high frequency
>> mappings. Since this does not affect the normal use-case where a "struct page"
>> is available, the performance of this API will be handled by a seperate patch
>> series.
>
> How (if any) does it affect performance?
This is for Amazon's super special userspace sauce. It doesn't affect
performance for normal usecases.
Paolo
next prev parent reply other threads:[~2018-12-19 21:27 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-03 9:30 [PATCH v4 00/14] KVM/X86: Introduce a new guest mapping interface KarimAllah Ahmed
2018-12-03 9:30 ` [PATCH v4 01/14] X86/nVMX: handle_vmon: Read 4 bytes from guest memory KarimAllah Ahmed
2018-12-03 12:48 ` David Hildenbrand
2018-12-03 9:30 ` [PATCH v4 02/14] X86/nVMX: handle_vmptrld: Copy the VMCS12 directly " KarimAllah Ahmed
2018-12-03 12:59 ` David Hildenbrand
2018-12-05 23:10 ` Jim Mattson
2018-12-21 15:20 ` Paolo Bonzini
2019-01-03 14:22 ` Raslan, KarimAllah
2018-12-03 9:30 ` [PATCH v4 03/14] X86/nVMX: Update the PML table without mapping and unmapping the page KarimAllah Ahmed
2018-12-03 13:10 ` David Hildenbrand
2018-12-03 9:30 ` [PATCH v4 04/14] X86/KVM: Handle PFNs outside of kernel reach when touching GPTEs KarimAllah Ahmed
2018-12-03 9:30 ` [PATCH v4 05/14] KVM: Introduce a new guest mapping API KarimAllah Ahmed
2018-12-19 21:26 ` Paolo Bonzini
2018-12-03 9:30 ` [PATCH v4 06/14] KVM/nVMX: Use kvm_vcpu_map when mapping the L1 MSR bitmap KarimAllah Ahmed
2018-12-03 9:31 ` [PATCH v4 07/14] KVM/nVMX: Use kvm_vcpu_map when mapping the virtual APIC page KarimAllah Ahmed
2018-12-03 9:31 ` [PATCH v4 08/14] KVM/nVMX: Use kvm_vcpu_map when mapping the posted interrupt descriptor table KarimAllah Ahmed
2018-12-03 9:31 ` [PATCH v4 09/14] KVM/X86: Use kvm_vcpu_map in emulator_cmpxchg_emulated KarimAllah Ahmed
2018-12-03 9:31 ` [PATCH v4 10/14] KVM/X86: hyperv: Use kvm_vcpu_map in synic_clear_sint_msg_pending KarimAllah Ahmed
2018-12-03 9:31 ` [PATCH v4 11/14] KVM/X86: hyperv: Use kvm_vcpu_map in synic_deliver_msg KarimAllah Ahmed
2018-12-03 9:31 ` [PATCH v4 12/14] KVM/nSVM: Use the new mapping API for mapping guest memory KarimAllah Ahmed
2018-12-03 9:31 ` [PATCH v4 13/14] KVM/nVMX: Use kvm_vcpu_map for accessing the shadow VMCS KarimAllah Ahmed
2018-12-03 9:31 ` [PATCH v4 14/14] KVM/nVMX: Use kvm_vcpu_map for accessing the enhanced VMCS KarimAllah Ahmed
2018-12-06 17:46 ` Vitaly Kuznetsov
2018-12-06 16:01 ` [PATCH v4 00/14] KVM/X86: Introduce a new guest mapping interface Konrad Rzeszutek Wilk
2018-12-19 21:27 ` Paolo Bonzini [this message]
2018-12-21 15:22 ` Paolo Bonzini
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