linux-kernel - Re: [PATCH v3 07/27] KVM: VMX: Initialize VMCS FRED fields

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3bc22633-4f79-4930-8357-11e5074014ed@zytor.com>
Date: Tue, 22 Oct 2024 09:18:58 -0700
From: Xin Li <xin@...or.com>
To: Chao Gao <chao.gao@...el.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org, seanjc@...gle.com, pbonzini@...hat.com,
        corbet@....net, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
        luto@...nel.org, peterz@...radead.org, andrew.cooper3@...rix.com
Subject: Re: [PATCH v3 07/27] KVM: VMX: Initialize VMCS FRED fields

On 10/22/2024 2:06 AM, Chao Gao wrote:
>> @@ -1503,6 +1503,18 @@ void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu,
>> 				    (unsigned long)(cpu_entry_stack(cpu) + 1));
>> 		}
>>
>> +		/* Per-CPU FRED MSRs */
>> +		if (kvm_cpu_cap_has(X86_FEATURE_FRED)) {
>> +#ifdef CONFIG_X86_64
>> +			vmcs_write64(HOST_IA32_FRED_RSP1, __this_cpu_ist_top_va(DB));
>> +			vmcs_write64(HOST_IA32_FRED_RSP2, __this_cpu_ist_top_va(NMI));
>> +			vmcs_write64(HOST_IA32_FRED_RSP3, __this_cpu_ist_top_va(DF));
>> +#endif
>> +			vmcs_write64(HOST_IA32_FRED_SSP1, 0);
>> +			vmcs_write64(HOST_IA32_FRED_SSP2, 0);
>> +			vmcs_write64(HOST_IA32_FRED_SSP3, 0);
> 
> Given SSP[1-3] are constant for now, how about asserting that host SSP[1-3] are
> all zeros when KVM is loaded and moving their writes to vmx_set_constant_host_state()?

I like the idea :)