Messages in this thread | | | Date | Thu, 10 Aug 2023 09:12:41 +0800 | Subject | Re: [PATCH v5 04/19] KVM:x86: Refresh CPUID on write to guest MSR_IA32_XSS | From | "Yang, Weijiang" <> |
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On 8/10/2023 8:01 AM, Paolo Bonzini wrote: > On Wed, Aug 9, 2023 at 10:56 AM Yang, Weijiang <weijiang.yang@intel.com> wrote: >>> I'm pretty sure I've advocated for the exact opposite in the past, i.e. argued >>> that KVM's ABI is to not enforce ordering between KVM_SET_CPUID2 and KVM_SET_MSR. >>> But this is becoming untenable, juggling the dependencies in KVM is complex and >>> is going to result in a nasty bug at some point. >>> >>> For this series, lets just tighten the rules for XSS, i.e. drop the host_initated >>> exemption. And in a parallel/separate series, try to do a wholesale cleanup of >>> all the cases that essentially allow userspace to do KVM_SET_MSR before KVM_SET_CPUID2. >> OK, will do it for this series and investigate for other MSRs. >> Thanks! > Remember that, while the ordering between KVM_SET_CPUID2 and > KVM_SET_MSR must be enforced(*), the host_initiated path must allow > the default (generally 0) value. Yes, will take it, thanks! > Paolo > > (*) this means that you should check guest_cpuid_has even if > host_initiated == true. >
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