arch/x86/kvm/vmx/vmx.c

Source file repositories/reference/linux-study-clean/arch/x86/kvm/vmx/vmx.c

File Facts

System
Linux kernel
Corpus path
arch/x86/kvm/vmx/vmx.c
Extension
.c
Size
261660 bytes
Lines
8858
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

switch (l1tf_mitigation) {
		case L1TF_MITIGATION_OFF:
			l1tf = VMENTER_L1D_FLUSH_NEVER;
			break;
		case L1TF_MITIGATION_AUTO:
		case L1TF_MITIGATION_FLUSH_NOWARN:
		case L1TF_MITIGATION_FLUSH:
		case L1TF_MITIGATION_FLUSH_NOSMT:
			l1tf = VMENTER_L1D_FLUSH_COND;
			break;
		case L1TF_MITIGATION_FULL:
		case L1TF_MITIGATION_FULL_FORCE:
			l1tf = VMENTER_L1D_FLUSH_ALWAYS;
			break;
		}
	} else if (l1tf_mitigation == L1TF_MITIGATION_FULL_FORCE) {
		l1tf = VMENTER_L1D_FLUSH_ALWAYS;
	}

	if (l1tf != VMENTER_L1D_FLUSH_NEVER && !vmx_l1d_flush_pages &&
	    !boot_cpu_has(X86_FEATURE_FLUSH_L1D)) {
		/*
		 * This allocation for vmx_l1d_flush_pages is not tied to a VM
		 * lifetime and so should not be charged to a memcg.
		 */
		page = alloc_pages(GFP_KERNEL, L1D_CACHE_ORDER);
		if (!page)
			return -ENOMEM;
		vmx_l1d_flush_pages = page_address(page);

		/*
		 * Initialize each page with a different pattern in
		 * order to protect against KSM in the nested
		 * virtualization case.
		 */
		for (i = 0; i < 1u << L1D_CACHE_ORDER; ++i) {
			memset(vmx_l1d_flush_pages + i * PAGE_SIZE, i + 1,
			       PAGE_SIZE);
		}
	}

	l1tf_vmx_mitigation = l1tf;

	if (l1tf != VMENTER_L1D_FLUSH_NEVER)
		static_branch_enable(&vmx_l1d_should_flush);
	else
		static_branch_disable(&vmx_l1d_should_flush);

	if (l1tf == VMENTER_L1D_FLUSH_COND)
		static_branch_enable(&vmx_l1d_flush_cond);
	else
		static_branch_disable(&vmx_l1d_flush_cond);
	return 0;
}

static int vmx_setup_l1d_flush(void)
{
	/*
	 * Hand the parameter mitigation value in which was stored in the pre
	 * module init parser. If no parameter was given, it will contain
	 * 'auto' which will be turned into the default 'cond' mitigation mode.
	 */
	return __vmx_setup_l1d_flush(vmentry_l1d_flush_param);
}

static void vmx_cleanup_l1d_flush(void)
{
	if (vmx_l1d_flush_pages) {
		free_pages((unsigned long)vmx_l1d_flush_pages, L1D_CACHE_ORDER);
		vmx_l1d_flush_pages = NULL;
	}
	/* Restore state so sysfs ignores VMX */
	l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO;
}

static int vmentry_l1d_flush_parse(const char *s)
{
	unsigned int i;

	if (s) {
		for (i = 0; i < ARRAY_SIZE(vmentry_l1d_param); i++) {
			if (vmentry_l1d_param[i].for_parse &&
			    sysfs_streq(s, vmentry_l1d_param[i].option))
				return i;
		}
	}
	return -EINVAL;
}

static int vmentry_l1d_flush_set(const char *s, const struct kernel_param *kp)

Annotation

Implementation Notes