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: <ZxdrM9IV7iX02Of0@intel.com>
Date: Tue, 22 Oct 2024 17:06:59 +0800
From: Chao Gao <chao.gao@...el.com>
To: "Xin Li (Intel)" <xin@...or.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

>@@ -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()?

>+		}
>+
> 		vmx->loaded_vmcs->cpu = cpu;
> 	}
> }
>@@ -4366,6 +4378,12 @@ void vmx_set_constant_host_state(struct vcpu_vmx *vmx)
> 	 */
> 	vmcs_write16(HOST_DS_SELECTOR, 0);
> 	vmcs_write16(HOST_ES_SELECTOR, 0);
>+
>+	/* FRED CONFIG and STKLVLS are the same on all CPUs. */
>+	if (kvm_cpu_cap_has(X86_FEATURE_FRED)) {
>+		vmcs_write64(HOST_IA32_FRED_CONFIG, kvm_host.fred_config);
>+		vmcs_write64(HOST_IA32_FRED_STKLVLS, kvm_host.fred_stklvls);
>+	}
> #else
> 	vmcs_write16(HOST_DS_SELECTOR, __KERNEL_DS);  /* 22.2.4 */
> 	vmcs_write16(HOST_ES_SELECTOR, __KERNEL_DS);  /* 22.2.4 */