Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 352 insertions, 0 deletions

diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
new file mode 100644
index 000000000..0b5db4de4
--- /dev/null
+++ b/arch/x86/kvm/vmx/vmenter.S
@@ -0,0 +1,352 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm/bitsperlong.h>
+#include <asm/kvm_vcpu_regs.h>
+#include <asm/nospec-branch.h>
+#include <asm/percpu.h>
+#include <asm/segment.h>
+#include "kvm-asm-offsets.h"
+#include "run_flags.h"
+
+#define WORD_SIZE (BITS_PER_LONG / 8)
+
+#define VCPU_RAX	__VCPU_REGS_RAX * WORD_SIZE
+#define VCPU_RCX	__VCPU_REGS_RCX * WORD_SIZE
+#define VCPU_RDX	__VCPU_REGS_RDX * WORD_SIZE
+#define VCPU_RBX	__VCPU_REGS_RBX * WORD_SIZE
+/* Intentionally omit RSP as it's context switched by hardware */
+#define VCPU_RBP	__VCPU_REGS_RBP * WORD_SIZE
+#define VCPU_RSI	__VCPU_REGS_RSI * WORD_SIZE
+#define VCPU_RDI	__VCPU_REGS_RDI * WORD_SIZE
+
+#ifdef CONFIG_X86_64
+#define VCPU_R8		__VCPU_REGS_R8  * WORD_SIZE
+#define VCPU_R9		__VCPU_REGS_R9  * WORD_SIZE
+#define VCPU_R10	__VCPU_REGS_R10 * WORD_SIZE
+#define VCPU_R11	__VCPU_REGS_R11 * WORD_SIZE
+#define VCPU_R12	__VCPU_REGS_R12 * WORD_SIZE
+#define VCPU_R13	__VCPU_REGS_R13 * WORD_SIZE
+#define VCPU_R14	__VCPU_REGS_R14 * WORD_SIZE
+#define VCPU_R15	__VCPU_REGS_R15 * WORD_SIZE
+#endif
+
+.section .noinstr.text, "ax"
+
+/**
+ * __vmx_vcpu_run - Run a vCPU via a transition to VMX guest mode
+ * @vmx:	struct vcpu_vmx *
+ * @regs:	unsigned long * (to guest registers)
+ * @flags:	VMX_RUN_VMRESUME:	use VMRESUME instead of VMLAUNCH
+ *		VMX_RUN_SAVE_SPEC_CTRL: save guest SPEC_CTRL into vmx->spec_ctrl
+ *
+ * Returns:
+ *	0 on VM-Exit, 1 on VM-Fail
+ */
+SYM_FUNC_START(__vmx_vcpu_run)
+	push %_ASM_BP
+	mov  %_ASM_SP, %_ASM_BP
+#ifdef CONFIG_X86_64
+	push %r15
+	push %r14
+	push %r13
+	push %r12
+#else
+	push %edi
+	push %esi
+#endif
+	push %_ASM_BX
+
+	/* Save @vmx for SPEC_CTRL handling */
+	push %_ASM_ARG1
+
+	/* Save @flags for SPEC_CTRL handling */
+	push %_ASM_ARG3
+
+	/*
+	 * Save @regs, _ASM_ARG2 may be modified by vmx_update_host_rsp() and
+	 * @regs is needed after VM-Exit to save the guest's register values.
+	 */
+	push %_ASM_ARG2
+
+	/* Copy @flags to BL, _ASM_ARG3 is volatile. */
+	mov %_ASM_ARG3B, %bl
+
+	lea (%_ASM_SP), %_ASM_ARG2
+	call vmx_update_host_rsp
+
+	ALTERNATIVE "jmp .Lspec_ctrl_done", "", X86_FEATURE_MSR_SPEC_CTRL
+
+	/*
+	 * SPEC_CTRL handling: if the guest's SPEC_CTRL value differs from the
+	 * host's, write the MSR.
+	 *
+	 * IMPORTANT: To avoid RSB underflow attacks and any other nastiness,
+	 * there must not be any returns or indirect branches between this code
+	 * and vmentry.
+	 */
+	mov 2*WORD_SIZE(%_ASM_SP), %_ASM_DI
+	movl VMX_spec_ctrl(%_ASM_DI), %edi
+	movl PER_CPU_VAR(x86_spec_ctrl_current), %esi
+	cmp %edi, %esi
+	je .Lspec_ctrl_done
+	mov $MSR_IA32_SPEC_CTRL, %ecx
+	xor %edx, %edx
+	mov %edi, %eax
+	wrmsr
+
+.Lspec_ctrl_done:
+
+	/*
+	 * Since vmentry is serializing on affected CPUs, there's no need for
+	 * an LFENCE to stop speculation from skipping the wrmsr.
+	 */
+
+	/* Load @regs to RAX. */
+	mov (%_ASM_SP), %_ASM_AX
+
+	/* Check if vmlaunch or vmresume is needed */
+	testb $VMX_RUN_VMRESUME, %bl
+
+	/* Load guest registers.  Don't clobber flags. */
+	mov VCPU_RCX(%_ASM_AX), %_ASM_CX
+	mov VCPU_RDX(%_ASM_AX), %_ASM_DX
+	mov VCPU_RBX(%_ASM_AX), %_ASM_BX
+	mov VCPU_RBP(%_ASM_AX), %_ASM_BP
+	mov VCPU_RSI(%_ASM_AX), %_ASM_SI
+	mov VCPU_RDI(%_ASM_AX), %_ASM_DI
+#ifdef CONFIG_X86_64
+	mov VCPU_R8 (%_ASM_AX),  %r8
+	mov VCPU_R9 (%_ASM_AX),  %r9
+	mov VCPU_R10(%_ASM_AX), %r10
+	mov VCPU_R11(%_ASM_AX), %r11
+	mov VCPU_R12(%_ASM_AX), %r12
+	mov VCPU_R13(%_ASM_AX), %r13
+	mov VCPU_R14(%_ASM_AX), %r14
+	mov VCPU_R15(%_ASM_AX), %r15
+#endif
+	/* Load guest RAX.  This kills the @regs pointer! */
+	mov VCPU_RAX(%_ASM_AX), %_ASM_AX
+
+	/* Check EFLAGS.ZF from 'testb' above */
+	jz .Lvmlaunch
+
+	/*
+	 * After a successful VMRESUME/VMLAUNCH, control flow "magically"
+	 * resumes below at 'vmx_vmexit' due to the VMCS HOST_RIP setting.
+	 * So this isn't a typical function and objtool needs to be told to
+	 * save the unwind state here and restore it below.
+	 */
+	UNWIND_HINT_SAVE
+
+/*
+ * If VMRESUME/VMLAUNCH and corresponding vmexit succeed, execution resumes at
+ * the 'vmx_vmexit' label below.
+ */
+.Lvmresume:
+	vmresume
+	jmp .Lvmfail
+
+.Lvmlaunch:
+	vmlaunch
+	jmp .Lvmfail
+
+	_ASM_EXTABLE(.Lvmresume, .Lfixup)
+	_ASM_EXTABLE(.Lvmlaunch, .Lfixup)
+
+SYM_INNER_LABEL(vmx_vmexit, SYM_L_GLOBAL)
+
+	/* Restore unwind state from before the VMRESUME/VMLAUNCH. */
+	UNWIND_HINT_RESTORE
+	ENDBR
+
+	/* Temporarily save guest's RAX. */
+	push %_ASM_AX
+
+	/* Reload @regs to RAX. */
+	mov WORD_SIZE(%_ASM_SP), %_ASM_AX
+
+	/* Save all guest registers, including RAX from the stack */
+	pop           VCPU_RAX(%_ASM_AX)
+	mov %_ASM_CX, VCPU_RCX(%_ASM_AX)
+	mov %_ASM_DX, VCPU_RDX(%_ASM_AX)
+	mov %_ASM_BX, VCPU_RBX(%_ASM_AX)
+	mov %_ASM_BP, VCPU_RBP(%_ASM_AX)
+	mov %_ASM_SI, VCPU_RSI(%_ASM_AX)
+	mov %_ASM_DI, VCPU_RDI(%_ASM_AX)
+#ifdef CONFIG_X86_64
+	mov %r8,  VCPU_R8 (%_ASM_AX)
+	mov %r9,  VCPU_R9 (%_ASM_AX)
+	mov %r10, VCPU_R10(%_ASM_AX)
+	mov %r11, VCPU_R11(%_ASM_AX)
+	mov %r12, VCPU_R12(%_ASM_AX)
+	mov %r13, VCPU_R13(%_ASM_AX)
+	mov %r14, VCPU_R14(%_ASM_AX)
+	mov %r15, VCPU_R15(%_ASM_AX)
+#endif
+
+	/* Clear return value to indicate VM-Exit (as opposed to VM-Fail). */
+	xor %ebx, %ebx
+
+.Lclear_regs:
+	/* Discard @regs.  The register is irrelevant, it just can't be RBX. */
+	pop %_ASM_AX
+
+	/*
+	 * Clear all general purpose registers except RSP and RBX to prevent
+	 * speculative use of the guest's values, even those that are reloaded
+	 * via the stack.  In theory, an L1 cache miss when restoring registers
+	 * could lead to speculative execution with the guest's values.
+	 * Zeroing XORs are dirt cheap, i.e. the extra paranoia is essentially
+	 * free.  RSP and RBX are exempt as RSP is restored by hardware during
+	 * VM-Exit and RBX is explicitly loaded with 0 or 1 to hold the return
+	 * value.
+	 */
+	xor %eax, %eax
+	xor %ecx, %ecx
+	xor %edx, %edx
+	xor %ebp, %ebp
+	xor %esi, %esi
+	xor %edi, %edi
+#ifdef CONFIG_X86_64
+	xor %r8d,  %r8d
+	xor %r9d,  %r9d
+	xor %r10d, %r10d
+	xor %r11d, %r11d
+	xor %r12d, %r12d
+	xor %r13d, %r13d
+	xor %r14d, %r14d
+	xor %r15d, %r15d
+#endif
+
+	/*
+	 * IMPORTANT: RSB filling and SPEC_CTRL handling must be done before
+	 * the first unbalanced RET after vmexit!
+	 *
+	 * For retpoline or IBRS, RSB filling is needed to prevent poisoned RSB
+	 * entries and (in some cases) RSB underflow.
+	 *
+	 * eIBRS has its own protection against poisoned RSB, so it doesn't
+	 * need the RSB filling sequence.  But it does need to be enabled, and a
+	 * single call to retire, before the first unbalanced RET.
+         */
+
+	FILL_RETURN_BUFFER %_ASM_CX, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_VMEXIT,\
+			   X86_FEATURE_RSB_VMEXIT_LITE
+
+	pop %_ASM_ARG2	/* @flags */
+	pop %_ASM_ARG1	/* @vmx */
+
+	call vmx_spec_ctrl_restore_host
+
+	/* Put return value in AX */
+	mov %_ASM_BX, %_ASM_AX
+
+	pop %_ASM_BX
+#ifdef CONFIG_X86_64
+	pop %r12
+	pop %r13
+	pop %r14
+	pop %r15
+#else
+	pop %esi
+	pop %edi
+#endif
+	pop %_ASM_BP
+	RET
+
+.Lfixup:
+	cmpb $0, kvm_rebooting
+	jne .Lvmfail
+	ud2
+.Lvmfail:
+	/* VM-Fail: set return value to 1 */
+	mov $1, %_ASM_BX
+	jmp .Lclear_regs
+
+SYM_FUNC_END(__vmx_vcpu_run)
+
+
+.section .text, "ax"
+
+/**
+ * vmread_error_trampoline - Trampoline from inline asm to vmread_error()
+ * @field:	VMCS field encoding that failed
+ * @fault:	%true if the VMREAD faulted, %false if it failed
+
+ * Save and restore volatile registers across a call to vmread_error().  Note,
+ * all parameters are passed on the stack.
+ */
+SYM_FUNC_START(vmread_error_trampoline)
+	push %_ASM_BP
+	mov  %_ASM_SP, %_ASM_BP
+
+	push %_ASM_AX
+	push %_ASM_CX
+	push %_ASM_DX
+#ifdef CONFIG_X86_64
+	push %rdi
+	push %rsi
+	push %r8
+	push %r9
+	push %r10
+	push %r11
+#endif
+
+	/* Load @field and @fault to arg1 and arg2 respectively. */
+	mov 3*WORD_SIZE(%_ASM_BP), %_ASM_ARG2
+	mov 2*WORD_SIZE(%_ASM_BP), %_ASM_ARG1
+
+	call vmread_error
+
+	/* Zero out @fault, which will be popped into the result register. */
+	_ASM_MOV $0, 3*WORD_SIZE(%_ASM_BP)
+
+#ifdef CONFIG_X86_64
+	pop %r11
+	pop %r10
+	pop %r9
+	pop %r8
+	pop %rsi
+	pop %rdi
+#endif
+	pop %_ASM_DX
+	pop %_ASM_CX
+	pop %_ASM_AX
+	pop %_ASM_BP
+
+	RET
+SYM_FUNC_END(vmread_error_trampoline)
+
+SYM_FUNC_START(vmx_do_interrupt_nmi_irqoff)
+	/*
+	 * Unconditionally create a stack frame, getting the correct RSP on the
+	 * stack (for x86-64) would take two instructions anyways, and RBP can
+	 * be used to restore RSP to make objtool happy (see below).
+	 */
+	push %_ASM_BP
+	mov %_ASM_SP, %_ASM_BP
+
+#ifdef CONFIG_X86_64
+	/*
+	 * Align RSP to a 16-byte boundary (to emulate CPU behavior) before
+	 * creating the synthetic interrupt stack frame for the IRQ/NMI.
+	 */
+	and  $-16, %rsp
+	push $__KERNEL_DS
+	push %rbp
+#endif
+	pushf
+	push $__KERNEL_CS
+	CALL_NOSPEC _ASM_ARG1
+
+	/*
+	 * "Restore" RSP from RBP, even though IRET has already unwound RSP to
+	 * the correct value.  objtool doesn't know the callee will IRET and,
+	 * without the explicit restore, thinks the stack is getting walloped.
+	 * Using an unwind hint is problematic due to x86-64's dynamic alignment.
+	 */
+	mov %_ASM_BP, %_ASM_SP
+	pop %_ASM_BP
+	RET
+SYM_FUNC_END(vmx_do_interrupt_nmi_irqoff)