Merge tag 'kvm-x86-vmx-6.18' of https://github.com/kvm-x86/linux into HEAD

KVM VMX changes for 6.18

 - Add read/write helpers for MSRs that need to be accessed with preemption
   disable to prepare for virtualizing FRED RSP0.

 - Fix a bug where KVM would return 0/success from __tdx_bringup() on error,
   i.e. where KVM would load with enable_tdx=true despite TDX not being usable.

 - Minor cleanups.

Author: bonzini

arch/x86/kvm/vmx/tdx.c

@@ -2491,7 +2491,7 @@ static int __tdx_td_init(struct kvm *kvm, struct td_params *td_params,
 	/* TDVPS = TDVPR(4K page) + TDCX(multiple 4K pages), -1 for TDVPR. */
 	kvm_tdx->td.tdcx_nr_pages = tdx_sysinfo->td_ctrl.tdvps_base_size / PAGE_SIZE - 1;
 	tdcs_pages = kcalloc(kvm_tdx->td.tdcs_nr_pages, sizeof(*kvm_tdx->td.tdcs_pages),
-			     GFP_KERNEL | __GFP_ZERO);
+			     GFP_KERNEL);
 	if (!tdcs_pages)
 		goto free_tdr;
 
@@ -3471,12 +3471,11 @@ static int __init __tdx_bringup(void)
 	if (r)
 		goto tdx_bringup_err;
 
+	r = -EINVAL;
 	/* Get TDX global information for later use */
 	tdx_sysinfo = tdx_get_sysinfo();
-	if (WARN_ON_ONCE(!tdx_sysinfo)) {
-		r = -EINVAL;
+	if (WARN_ON_ONCE(!tdx_sysinfo))
 		goto get_sysinfo_err;
-	}
 
 	/* Check TDX module and KVM capabilities */
 	if (!tdx_get_supported_attrs(&tdx_sysinfo->td_conf) ||
@@ -3519,14 +3518,11 @@ static int __init __tdx_bringup(void)
 	if (td_conf->max_vcpus_per_td < num_present_cpus()) {
 		pr_err("Disable TDX: MAX_VCPU_PER_TD (%u) smaller than number of logical CPUs (%u).\n",
 				td_conf->max_vcpus_per_td, num_present_cpus());
-		r = -EINVAL;
 		goto get_sysinfo_err;
 	}
 
-	if (misc_cg_set_capacity(MISC_CG_RES_TDX, tdx_get_nr_guest_keyids())) {
-		r = -EINVAL;
+	if (misc_cg_set_capacity(MISC_CG_RES_TDX, tdx_get_nr_guest_keyids()))
 		goto get_sysinfo_err;
-	}
 
 	/*
 	 * Leave hardware virtualization enabled after TDX is enabled

arch/x86/kvm/vmx/vmx.c

@@ -1344,22 +1344,35 @@ static void vmx_prepare_switch_to_host(struct vcpu_vmx *vmx)
 }
 
 #ifdef CONFIG_X86_64
-static u64 vmx_read_guest_kernel_gs_base(struct vcpu_vmx *vmx)
+static u64 vmx_read_guest_host_msr(struct vcpu_vmx *vmx, u32 msr, u64 *cache)
 {
 	preempt_disable();
 	if (vmx->vt.guest_state_loaded)
-		rdmsrq(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
+		*cache = read_msr(msr);
 	preempt_enable();
-	return vmx->msr_guest_kernel_gs_base;
+	return *cache;
 }
 
-static void vmx_write_guest_kernel_gs_base(struct vcpu_vmx *vmx, u64 data)
+static void vmx_write_guest_host_msr(struct vcpu_vmx *vmx, u32 msr, u64 data,
+				     u64 *cache)
 {
 	preempt_disable();
 	if (vmx->vt.guest_state_loaded)
-		wrmsrq(MSR_KERNEL_GS_BASE, data);
+		wrmsrns(msr, data);
 	preempt_enable();
-	vmx->msr_guest_kernel_gs_base = data;
+	*cache = data;
+}
+
+static u64 vmx_read_guest_kernel_gs_base(struct vcpu_vmx *vmx)
+{
+	return vmx_read_guest_host_msr(vmx, MSR_KERNEL_GS_BASE,
+				       &vmx->msr_guest_kernel_gs_base);
+}
+
+static void vmx_write_guest_kernel_gs_base(struct vcpu_vmx *vmx, u64 data)
+{
+	vmx_write_guest_host_msr(vmx, MSR_KERNEL_GS_BASE, data,
+				 &vmx->msr_guest_kernel_gs_base);
 }
 #endif
 
@@ -8532,7 +8545,9 @@ __init int vmx_hardware_setup(void)
 	 */
 	if (!static_cpu_has(X86_FEATURE_SELFSNOOP))
 		kvm_caps.supported_quirks &= ~KVM_X86_QUIRK_IGNORE_GUEST_PAT;
-       kvm_caps.inapplicable_quirks &= ~KVM_X86_QUIRK_IGNORE_GUEST_PAT;
+
+	kvm_caps.inapplicable_quirks &= ~KVM_X86_QUIRK_IGNORE_GUEST_PAT;
+
 	return r;
 }