From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH v6 00/14] KVM/X86: Introduce a new guest mapping interface Date: Mon, 18 Mar 2019 10:22:32 -0400 Message-ID: <20190318142232.GC16697@char.us.oracle.com> References: <1548966284-28642-1-git-send-email-karahmed@amazon.de> <1552914624.8242.1.camel@amazon.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , "rkrcmar@redhat.com" , "pbonzini@redhat.com" , "x86@kernel.org" To: "Raslan, KarimAllah" Return-path: Content-Disposition: inline In-Reply-To: <1552914624.8242.1.camel@amazon.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Mon, Mar 18, 2019 at 01:10:24PM +0000, Raslan, KarimAllah wrote: > I guess this patch series missed the 5.1 merge window? :) Were there any outstanding fixes that had to be addressed? > > On Thu, 2019-01-31 at 21:24 +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. Patch 2 is additionally fixing an > > incorrect page release and marking the page as dirty (i.e. as a side-effect of > > using the helper function to write). > > > > 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. > > > > So the simple way to use memory outside kernel control is: > > > > 1- Pass 'mem=' in the kernel command-line to limit the amount of memory managed > > by the kernel. > > 2- Map this physical memory you want to give to the guest with: > > mmap("/dev/mem", physical_address_offset, ..) > > 3- Use the user-space virtual address as the "userspace_addr" field in > > KVM_SET_USER_MEMORY_REGION ioctl. > > > > v5 -> v6: > > - Added one extra patch to ensure that support for this mem= case is complete > > for x86. > > - Added a helper function to check if the mapping is mapped or not. > > - Added more comments on the struct. > > - Setting ->page to NULL on unmap and to a poison ptr if unused during map > > - Checking for map ptr before using it. > > - Change kvm_vcpu_unmap to also mark page dirty for LM. That requires > > passing the vCPU pointer again to this function. > > > > v4 -> v5: > > - Introduce a new parameter 'dirty' into kvm_vcpu_unmap > > - A horrible rebase due to nested.c :) > > - Dropped a couple of hyperv patches as the code was fixed already as a > > side-effect of another patch. > > - Added a new trivial cleanup patch. > > > > v3 -> v4: > > - Rebase > > - Add a new patch to also fix the newly introduced enlightned VMCS. > > > > v2 -> v3: > > - Rebase > > - Add a new patch to also fix the newly introduced shadow VMCS. > > > > Filippo Sironi (1): > > X86/KVM: Handle PFNs outside of kernel reach when touching GPTEs > > > > KarimAllah Ahmed (13): > > X86/nVMX: handle_vmon: Read 4 bytes from guest memory > > X86/nVMX: Update the PML table without mapping and unmapping the page > > KVM: Introduce a new guest mapping API > > X86/nVMX: handle_vmptrld: Use kvm_vcpu_map when copying VMCS12 from > > guest memory > > KVM/nVMX: Use kvm_vcpu_map when mapping the L1 MSR bitmap > > KVM/nVMX: Use kvm_vcpu_map when mapping the virtual APIC page > > KVM/nVMX: Use kvm_vcpu_map when mapping the posted interrupt > > descriptor table > > KVM/X86: Use kvm_vcpu_map in emulator_cmpxchg_emulated > > KVM/nSVM: Use the new mapping API for mapping guest memory > > KVM/nVMX: Use kvm_vcpu_map for accessing the shadow VMCS > > KVM/nVMX: Use kvm_vcpu_map for accessing the enlightened VMCS > > KVM/nVMX: Use page_address_valid in a few more locations > > kvm, x86: Properly check whether a pfn is an MMIO or not > > > > arch/x86/include/asm/e820/api.h | 1 + > > arch/x86/kernel/e820.c | 18 ++++- > > arch/x86/kvm/mmu.c | 5 +- > > arch/x86/kvm/paging_tmpl.h | 38 +++++++--- > > arch/x86/kvm/svm.c | 97 ++++++++++++------------ > > arch/x86/kvm/vmx/nested.c | 160 +++++++++++++++------------------------- > > arch/x86/kvm/vmx/vmx.c | 19 ++--- > > arch/x86/kvm/vmx/vmx.h | 9 ++- > > arch/x86/kvm/x86.c | 14 ++-- > > include/linux/kvm_host.h | 28 +++++++ > > virt/kvm/kvm_main.c | 64 ++++++++++++++++ > > 11 files changed, 267 insertions(+), 186 deletions(-) > > > > > > Amazon Development Center Germany GmbH > Krausenstr. 38 > 10117 Berlin > Geschaeftsfuehrer: Christian Schlaeger, Ralf Herbrich > Ust-ID: DE 289 237 879 > Eingetragen am Amtsgericht Charlottenburg HRB 149173 B >