From: Chao Gao <chao.gao@intel.com>
To: Robert Hoo <robert.hu@linux.intel.com>
Cc: <seanjc@google.com>, <pbonzini@redhat.com>,
<yu.c.zhang@linux.intel.com>, <yuan.yao@linux.intel.com>,
<jingqi.liu@intel.com>, <weijiang.yang@intel.com>,
<isaku.yamahata@intel.com>, <kirill.shutemov@linux.intel.com>,
<kvm@vger.kernel.org>
Subject: Re: [PATCH v4 0/9] Linear Address Masking (LAM) KVM Enabling
Date: Thu, 9 Feb 2023 14:15:42 +0800 [thread overview]
Message-ID: <Y+SPjkY87zzFqHLj@gao-cwp> (raw)
In-Reply-To: <20230209024022.3371768-1-robert.hu@linux.intel.com>
On Thu, Feb 09, 2023 at 10:40:13AM +0800, Robert Hoo wrote:
>Intercept CR4.LAM_SUP by KVM, to avoid read VMCS field every time, with
>expectation that guest won't toggle this bit frequently.
>
>Under EPT mode, CR3 is fully under guest control, guest LAM is thus transparent to
>KVM. Nothing more need to do.
I don't think it is correct. You have to strip LAM_U57/U48 from CR3 when
walking guest page table and strip metadata from pointers when emulating
instructions.
>
>For Shadow paging (EPT = off), KVM need to handle guest CR3.LAM_U48 and CR3.LAM_U57
>toggles.
>
>[1] ISE Chap10 https://cdrdv2.intel.com/v1/dl/getContent/671368 (Section 10.6 VMX interaction)
>[2] Thus currently, Kernel enabling patch only enables LAM_U57. https://lore.kernel.org/lkml/20230123220500.21077-1-kirill.shutemov@linux.intel.com/
Please add a kvm-unit-test or kselftest for LAM, particularly for
operations (e.g., canonical check for supervisor pointers, toggle
CR4.LAM_SUP) which aren't covered by the test in Kirill's series.
next prev parent reply other threads:[~2023-02-09 6:15 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-09 2:40 [PATCH v4 0/9] Linear Address Masking (LAM) KVM Enabling Robert Hoo
2023-02-09 2:40 ` [PATCH v4 1/9] KVM: x86: Intercept CR4.LAM_SUP when LAM feature is enabled in guest Robert Hoo
2023-02-09 9:21 ` Chao Gao
2023-02-09 12:48 ` Robert Hoo
2023-02-10 3:29 ` Yang, Weijiang
2023-02-10 5:02 ` Robert Hoo
2023-02-10 16:30 ` Sean Christopherson
2023-02-14 1:27 ` Binbin Wu
2023-02-14 6:11 ` Robert Hoo
2023-02-14 9:00 ` Binbin Wu
2023-02-14 12:24 ` Robert Hoo
2023-02-14 12:36 ` Robert Hoo
2023-02-16 5:31 ` Binbin Wu
2023-02-16 5:54 ` Robert Hoo
2023-02-09 2:40 ` [PATCH v4 2/9] KVM: x86: MMU: Clear CR3 LAM bits when allocate shadow root Robert Hoo
2023-02-09 9:55 ` Chao Gao
2023-02-09 13:02 ` Robert Hoo
2023-02-14 2:55 ` Binbin Wu
2023-02-15 1:17 ` Robert Hoo
2023-02-16 2:14 ` Robert Hoo
2023-02-10 3:38 ` Yang, Weijiang
2023-02-11 3:12 ` Robert Hoo
2023-02-09 2:40 ` [PATCH v4 3/9] KVM: x86: MMU: Commets update Robert Hoo
2023-02-10 6:59 ` Chao Gao
2023-02-10 7:55 ` Robert Hoo
2023-02-10 16:54 ` Sean Christopherson
2023-02-09 2:40 ` [PATCH v4 4/9] KVM: x86: MMU: Integrate LAM bits when build guest CR3 Robert Hoo
2023-02-10 14:04 ` Chao Gao
2023-02-11 6:24 ` Robert Hoo
2023-02-11 6:29 ` Robert Hoo
2023-02-09 2:40 ` [PATCH v4 5/9] KVM: x86: Untag LAM bits when applicable Robert Hoo
2023-02-10 15:04 ` Chao Gao
2023-02-11 5:57 ` Robert Hoo
2023-02-16 6:37 ` Binbin Wu
2023-02-09 2:40 ` [PATCH v4 6/9] KVM: x86: When KVM judges CR3 valid or not, consider LAM bits Robert Hoo
2023-02-13 2:01 ` Chao Gao
2023-02-13 13:25 ` Robert Hoo
2023-02-14 6:18 ` Chao Gao
2023-02-14 7:00 ` Chao Gao
2023-02-18 5:44 ` Robert Hoo
2023-02-09 2:40 ` [PATCH v4 7/9] KVM: x86: When guest set CR3, handle LAM bits semantics Robert Hoo
2023-02-13 3:31 ` Chao Gao
2023-02-14 5:28 ` Robert Hoo
2023-02-14 6:48 ` Chao Gao
2023-02-09 2:40 ` [PATCH v4 8/9] KVM: x86: emulation: Apply LAM when emulating data access Robert Hoo
2023-02-13 3:53 ` Chao Gao
2023-02-14 5:38 ` Robert Hoo
2023-02-09 2:40 ` [PATCH v4 9/9] KVM: x86: LAM: Expose LAM CPUID to user space VMM Robert Hoo
2023-02-21 5:47 ` Binbin Wu
2023-02-21 7:26 ` Robert Hoo
2023-02-21 8:26 ` Binbin Wu
2023-02-21 11:13 ` Yu Zhang
2023-02-21 13:18 ` Binbin Wu
2023-02-21 14:36 ` Robert Hoo
2023-02-09 6:15 ` Chao Gao [this message]
2023-02-09 12:25 ` [PATCH v4 0/9] Linear Address Masking (LAM) KVM Enabling Robert Hoo
2023-02-09 17:27 ` Sean Christopherson
2023-02-10 2:07 ` Robert Hoo
2023-02-10 3:17 ` Chao Gao
2023-02-10 8:41 ` Robert Hoo
2023-02-10 8:39 ` Robert Hoo
2023-02-10 9:22 ` Chao Gao
2023-02-13 9:02 ` Binbin Wu
2023-02-13 13:16 ` Robert Hoo
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