1 files changed, 106 insertions, 0 deletions
diff --git a/arch/x86/kernel/paravirt_patch.c b/arch/x86/kernel/paravirt_patch.c
new file mode 100644
index 000000000..7c518b08a
--- /dev/null
+++ b/arch/x86/kernel/paravirt_patch.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/stringify.h>
+
+#include <asm/paravirt.h>
+#include <asm/asm-offsets.h>
+
+#define PSTART(d, m)							\
+	patch_data_##d.m
+
+#define PEND(d, m)							\
+	(PSTART(d, m) + sizeof(patch_data_##d.m))
+
+#define PATCH(d, m, insn_buff, len)						\
+	paravirt_patch_insns(insn_buff, len, PSTART(d, m), PEND(d, m))
+
+#define PATCH_CASE(ops, m, data, insn_buff, len)				\
+	case PARAVIRT_PATCH(ops.m):					\
+		return PATCH(data, ops##_##m, insn_buff, len)
+
+#ifdef CONFIG_PARAVIRT_XXL
+struct patch_xxl {
+	const unsigned char	irq_irq_disable[1];
+	const unsigned char	irq_irq_enable[1];
+	const unsigned char	irq_save_fl[2];
+	const unsigned char	mmu_read_cr2[3];
+	const unsigned char	mmu_read_cr3[3];
+	const unsigned char	mmu_write_cr3[3];
+	const unsigned char	irq_restore_fl[2];
+	const unsigned char	cpu_wbinvd[2];
+	const unsigned char	cpu_usergs_sysret64[6];
+	const unsigned char	mov64[3];
+};
+
+static const struct patch_xxl patch_data_xxl = {
+	.irq_irq_disable	= { 0xfa },		// cli
+	.irq_irq_enable		= { 0xfb },		// sti
+	.irq_save_fl		= { 0x9c, 0x58 },	// pushf; pop %[re]ax
+	.mmu_read_cr2		= { 0x0f, 0x20, 0xd0 },	// mov %cr2, %[re]ax
+	.mmu_read_cr3		= { 0x0f, 0x20, 0xd8 },	// mov %cr3, %[re]ax
+	.mmu_write_cr3		= { 0x0f, 0x22, 0xdf },	// mov %rdi, %cr3
+	.irq_restore_fl		= { 0x57, 0x9d },	// push %rdi; popfq
+	.cpu_wbinvd		= { 0x0f, 0x09 },	// wbinvd
+	.cpu_usergs_sysret64	= { 0x0f, 0x01, 0xf8,
+				    0x48, 0x0f, 0x07 },	// swapgs; sysretq
+	.mov64			= { 0x48, 0x89, 0xf8 },	// mov %rdi, %rax
+};
+
+unsigned int paravirt_patch_ident_64(void *insn_buff, unsigned int len)
+{
+	return PATCH(xxl, mov64, insn_buff, len);
+}
+# endif /* CONFIG_PARAVIRT_XXL */
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+struct patch_lock {
+	unsigned char queued_spin_unlock[3];
+	unsigned char vcpu_is_preempted[2];
+};
+
+static const struct patch_lock patch_data_lock = {
+	.vcpu_is_preempted	= { 0x31, 0xc0 },	// xor %eax, %eax
+
+# ifdef CONFIG_X86_64
+	.queued_spin_unlock	= { 0xc6, 0x07, 0x00 },	// movb $0, (%rdi)
+# else
+	.queued_spin_unlock	= { 0xc6, 0x00, 0x00 },	// movb $0, (%eax)
+# endif
+};
+#endif /* CONFIG_PARAVIRT_SPINLOCKS */
+
+unsigned int native_patch(u8 type, void *insn_buff, unsigned long addr,
+			  unsigned int len)
+{
+	switch (type) {
+
+#ifdef CONFIG_PARAVIRT_XXL
+	PATCH_CASE(irq, restore_fl, xxl, insn_buff, len);
+	PATCH_CASE(irq, save_fl, xxl, insn_buff, len);
+	PATCH_CASE(irq, irq_enable, xxl, insn_buff, len);
+	PATCH_CASE(irq, irq_disable, xxl, insn_buff, len);
+
+	PATCH_CASE(mmu, read_cr2, xxl, insn_buff, len);
+	PATCH_CASE(mmu, read_cr3, xxl, insn_buff, len);
+	PATCH_CASE(mmu, write_cr3, xxl, insn_buff, len);
+
+	PATCH_CASE(cpu, usergs_sysret64, xxl, insn_buff, len);
+	PATCH_CASE(cpu, wbinvd, xxl, insn_buff, len);
+#endif
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+	case PARAVIRT_PATCH(lock.queued_spin_unlock):
+		if (pv_is_native_spin_unlock())
+			return PATCH(lock, queued_spin_unlock, insn_buff, len);
+		break;
+
+	case PARAVIRT_PATCH(lock.vcpu_is_preempted):
+		if (pv_is_native_vcpu_is_preempted())
+			return PATCH(lock, vcpu_is_preempted, insn_buff, len);
+		break;
+#endif
+	default:
+		break;
+	}
+
+	return paravirt_patch_default(type, insn_buff, addr, len);
+}