From: Jim Mattson <jmattson@google.com>
To: KarimAllah Ahmed <karahmed@amazon.de>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
"kvm list" <kvm@vger.kernel.org>
Subject: Re: [PATCH v4 02/14] X86/nVMX: handle_vmptrld: Copy the VMCS12 directly from guest memory
Date: Wed, 5 Dec 2018 15:10:02 -0800 [thread overview]
Message-ID: <CALMp9eSX99cd3-XCCJOySVPXwxt=fx0zOczzq0ictDFNU1rqNw@mail.gmail.com> (raw)
In-Reply-To: <1543829467-18025-3-git-send-email-karahmed@amazon.de>
On Mon, Dec 3, 2018 at 1:31 AM KarimAllah Ahmed <karahmed@amazon.de> wrote:
>
> Copy the VMCS12 directly from guest memory instead of the map->copy->unmap
> sequence. This also avoids using kvm_vcpu_gpa_to_page() and kmap() which
> assumes that there is a "struct page" for guest memory.
>
> Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
> ---
> v3 -> v4:
> - Return VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID on failure (jmattson@)
> v1 -> v2:
> - Massage commit message a bit.
> ---
> arch/x86/kvm/vmx.c | 24 ++++++++++++------------
> 1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index b84f230..75817cb 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -9301,20 +9301,22 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
> return 1;
>
> if (vmx->nested.current_vmptr != vmptr) {
> - struct vmcs12 *new_vmcs12;
> - struct page *page;
> - page = kvm_vcpu_gpa_to_page(vcpu, vmptr);
> - if (is_error_page(page))
> - return nested_vmx_failInvalid(vcpu);
> + struct vmcs12 *new_vmcs12 = (struct vmcs12 *)__get_free_page(GFP_KERNEL);
> +
> + if (!new_vmcs12 ||
> + kvm_read_guest(vcpu->kvm, vmptr, new_vmcs12,
> + sizeof(*new_vmcs12))) {
Isn't this a lot slower than kmap() when there is a struct page?
> + free_page((unsigned long)new_vmcs12);
> + return nested_vmx_failValid(vcpu,
> + VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
I agree with David that this isn't the right thing to do for -ENOMEM.
next prev parent reply other threads:[~2018-12-05 23:10 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 [this message]
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
2018-12-21 15:22 ` Paolo Bonzini
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