lkml.org 
[lkml]   [2018]   [Feb]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [RFC 00/12] KVM/X86: Introduce a new guest mapping API
From
Date
On Mon, 2018-02-05 at 19:47 +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".

In cases where there is no 'struct page', would it be possible to get
two VM-s to share memory (in the way Xen's grant tables do)?

We are working on a page sharing mechanism and would like to know if
this use case can be accommodated.

Thank you,

> This patchset introduces a new mapping function to map guest memory into host
> kernel memory. Ideally I should also get rid of all guest mapping functions
> that end up converting a guest address to a page, but I decided to get feedback
> on this first and see if this is an acceptable API.
>
> Most of the offending code paths that has been updated are in the nested code
> base. Mostly because I stumbled upon this code while looking at the nested MSR
> bitmap handling for the IBRS patches. There are also offending code paths in
> SVM code, but I will do that once the interface is accepted.
>
> KarimAllah Ahmed (12):
> KVM: Introduce helper functions to map/unmap guest memory
> KVM/VMX: Use the new host mapping API for apic_access_page
> KVM/VMX: Use the new host mapping API for virtual_apic_page
> KVM/VMX: Use the new host mapping API for pi_desc_page
> KVM/VMX: Use the new host mapping API for mapping nested vmptr
> KVM/VMX: Use the new host mapping API for handle_vmptrld
> KVM/VMX: Use the new host mapping API for mapping L12 MSR bitmap
> KVM/VMX: Use the new host mapping API for mapping nested PML
> KVM/VMX: Use the new host mapping API for cmpxchg_emulated
> KVM/VMX: Use the new host mapping API for synic_clear_sint_msg_pending
> KVM/VMX: Use the new host mapping API for synic_deliver_msg
> KVM/VMX: Remove kvm_vcpu_gpa_to_page as it is now unused
>
> arch/x86/kvm/hyperv.c | 24 +++----
> arch/x86/kvm/vmx.c | 159 ++++++++++++++++++++---------------------------
> arch/x86/kvm/x86.c | 12 ++--
> include/linux/kvm_host.h | 18 +++++-
> virt/kvm/kvm_main.c | 62 ++++++++++++++++++
> 5 files changed, 161 insertions(+), 114 deletions(-)
>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: kvm@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org

--
Mihai Donțu

\
 
 \ /
  Last update: 2018-02-05 20:33    [W:0.111 / U:0.908 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site