From: Paolo Bonzini <pbonzini@redhat.com>
To: Mohammed Gamal <mgamal@redhat.com>, kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, vkuznets@redhat.com,
sean.j.christopherson@intel.com, wanpengli@tencent.com,
jmattson@google.com, joro@8bytes.org
Subject: Re: [PATCH v3 0/9] KVM: Support guest MAXPHYADDR < host MAXPHYADDR
Date: Fri, 10 Jul 2020 19:49:12 +0200 [thread overview]
Message-ID: <69f44e48-4609-ff64-56a9-ce72e1f483fa@redhat.com> (raw)
In-Reply-To: <20200710154811.418214-1-mgamal@redhat.com>
On 10/07/20 17:48, Mohammed Gamal wrote:
> When EPT is enabled, KVM does not really look at guest physical
> address size. Address bits above maximum physical memory size are reserved.
> Because KVM does not look at these guest physical addresses, it currently
> effectively supports guest physical address sizes equal to the host.
>
> This can be problem when having a mixed setup of machines with 5-level page
> tables and machines with 4-level page tables, as live migration can change
> MAXPHYADDR while the guest runs, which can theoretically introduce bugs.
>
> In this patch series we add checks on guest physical addresses in EPT
> violation/misconfig and NPF vmexits and if needed inject the proper
> page faults in the guest.
>
> A more subtle issue is when the host MAXPHYADDR is larger than that of the
> guest. Page faults caused by reserved bits on the guest won't cause an EPT
> violation/NPF and hence we also check guest MAXPHYADDR and add PFERR_RSVD_MASK
> error code to the page fault if needed.
>
> ----
>
> Changes from v2:
> - Drop support for this feature on AMD processors after discussion with AMD
>
>
> Mohammed Gamal (5):
> KVM: x86: Add helper functions for illegal GPA checking and page fault
> injection
> KVM: x86: mmu: Move translate_gpa() to mmu.c
> KVM: x86: mmu: Add guest physical address check in translate_gpa()
> KVM: VMX: Add guest physical address check in EPT violation and
> misconfig
> KVM: x86: SVM: VMX: Make GUEST_MAXPHYADDR < HOST_MAXPHYADDR support
> configurable
>
> Paolo Bonzini (4):
> KVM: x86: rename update_bp_intercept to update_exception_bitmap
> KVM: x86: update exception bitmap on CPUID changes
> KVM: VMX: introduce vmx_need_pf_intercept
> KVM: VMX: optimize #PF injection when MAXPHYADDR does not match
>
> arch/x86/include/asm/kvm_host.h | 10 ++------
> arch/x86/kvm/cpuid.c | 2 ++
> arch/x86/kvm/mmu.h | 6 +++++
> arch/x86/kvm/mmu/mmu.c | 12 +++++++++
> arch/x86/kvm/svm/svm.c | 22 +++++++++++++---
> arch/x86/kvm/vmx/nested.c | 28 ++++++++++++--------
> arch/x86/kvm/vmx/vmx.c | 45 +++++++++++++++++++++++++++++----
> arch/x86/kvm/vmx/vmx.h | 6 +++++
> arch/x86/kvm/x86.c | 29 ++++++++++++++++++++-
> arch/x86/kvm/x86.h | 1 +
> include/uapi/linux/kvm.h | 1 +
> 11 files changed, 133 insertions(+), 29 deletions(-)
>
Queued, thanks (I'll look at it more closely when I'm back, but at least
people can play with it).
Paolo
prev parent reply other threads:[~2020-07-10 17:49 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-10 15:48 [PATCH v3 0/9] KVM: Support guest MAXPHYADDR < host MAXPHYADDR Mohammed Gamal
2020-07-10 15:48 ` [PATCH v3 1/9] KVM: x86: Add helper functions for illegal GPA checking and page fault injection Mohammed Gamal
2020-07-10 15:48 ` [PATCH v3 2/9] KVM: x86: mmu: Move translate_gpa() to mmu.c Mohammed Gamal
2020-07-10 15:48 ` [PATCH v3 3/9] KVM: x86: mmu: Add guest physical address check in translate_gpa() Mohammed Gamal
2020-07-10 17:41 ` Paolo Bonzini
2020-07-10 15:48 ` [PATCH v3 4/9] KVM: x86: rename update_bp_intercept to update_exception_bitmap Mohammed Gamal
2020-07-10 16:15 ` Jim Mattson
2020-07-10 15:48 ` [PATCH v3 5/9] KVM: x86: update exception bitmap on CPUID changes Mohammed Gamal
2020-07-10 16:25 ` Jim Mattson
2020-07-10 15:48 ` [PATCH v3 6/9] KVM: VMX: introduce vmx_need_pf_intercept Mohammed Gamal
2020-07-10 15:48 ` [PATCH v3 7/9] KVM: VMX: Add guest physical address check in EPT violation and misconfig Mohammed Gamal
2020-07-13 18:32 ` Sean Christopherson
2020-07-15 23:00 ` Sean Christopherson
2020-08-17 17:22 ` Sean Christopherson
2020-08-17 18:01 ` Paolo Bonzini
2020-10-09 16:17 ` Jim Mattson
2020-10-14 23:44 ` Jim Mattson
2020-10-23 3:14 ` Sean Christopherson
2020-10-23 9:22 ` Paolo Bonzini
2020-10-23 16:59 ` Jim Mattson
2020-10-23 17:16 ` Paolo Bonzini
2020-10-23 17:23 ` Jim Mattson
2020-10-23 17:43 ` Paolo Bonzini
2021-01-15 19:35 ` Jim Mattson
2021-01-20 21:16 ` Jim Mattson
2021-01-27 20:57 ` Jim Mattson
2021-06-21 18:31 ` Jim Mattson
2020-07-10 15:48 ` [PATCH v3 8/9] KVM: VMX: optimize #PF injection when MAXPHYADDR does not match Mohammed Gamal
2020-07-10 15:48 ` [PATCH v3 9/9] KVM: x86: SVM: VMX: Make GUEST_MAXPHYADDR < HOST_MAXPHYADDR support configurable Mohammed Gamal
2020-07-10 17:40 ` Paolo Bonzini
2020-07-10 16:30 ` [PATCH v3 0/9] KVM: Support guest MAXPHYADDR < host MAXPHYADDR Jim Mattson
2020-07-10 17:06 ` Paolo Bonzini
2020-07-10 17:13 ` Jim Mattson
2020-07-10 17:16 ` Paolo Bonzini
2020-07-10 17:26 ` Sean Christopherson
2020-07-10 17:26 ` Jim Mattson
2020-07-10 17:40 ` Paolo Bonzini
2020-07-10 17:49 ` Paolo Bonzini [this message]
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