| /* 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> |
| |
| #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 |
| |
| .text |
| |
| /** |
| * vmx_vmenter - VM-Enter the current loaded VMCS |
| * |
| * %RFLAGS.ZF: !VMCS.LAUNCHED, i.e. controls VMLAUNCH vs. VMRESUME |
| * |
| * Returns: |
| * %RFLAGS.CF is set on VM-Fail Invalid |
| * %RFLAGS.ZF is set on VM-Fail Valid |
| * %RFLAGS.{CF,ZF} are cleared on VM-Success, i.e. VM-Exit |
| * |
| * Note that VMRESUME/VMLAUNCH fall-through and return directly if |
| * they VM-Fail, whereas a successful VM-Enter + VM-Exit will jump |
| * to vmx_vmexit. |
| */ |
| SYM_FUNC_START(vmx_vmenter) |
| /* EFLAGS.ZF is set if VMCS.LAUNCHED == 0 */ |
| je 2f |
| |
| 1: vmresume |
| ret |
| |
| 2: vmlaunch |
| ret |
| |
| 3: cmpb $0, kvm_rebooting |
| je 4f |
| ret |
| 4: ud2 |
| |
| _ASM_EXTABLE(1b, 3b) |
| _ASM_EXTABLE(2b, 3b) |
| |
| SYM_FUNC_END(vmx_vmenter) |
| |
| /** |
| * vmx_vmexit - Handle a VMX VM-Exit |
| * |
| * Returns: |
| * %RFLAGS.{CF,ZF} are cleared on VM-Success, i.e. VM-Exit |
| * |
| * This is vmx_vmenter's partner in crime. On a VM-Exit, control will jump |
| * here after hardware loads the host's state, i.e. this is the destination |
| * referred to by VMCS.HOST_RIP. |
| */ |
| SYM_FUNC_START(vmx_vmexit) |
| #ifdef CONFIG_RETPOLINE |
| ALTERNATIVE "jmp .Lvmexit_skip_rsb", "", X86_FEATURE_RETPOLINE |
| /* Preserve guest's RAX, it's used to stuff the RSB. */ |
| push %_ASM_AX |
| |
| /* IMPORTANT: Stuff the RSB immediately after VM-Exit, before RET! */ |
| FILL_RETURN_BUFFER %_ASM_AX, RSB_CLEAR_LOOPS, X86_FEATURE_RETPOLINE |
| |
| /* Clear RFLAGS.CF and RFLAGS.ZF to preserve VM-Exit, i.e. !VM-Fail. */ |
| or $1, %_ASM_AX |
| |
| pop %_ASM_AX |
| .Lvmexit_skip_rsb: |
| #endif |
| ret |
| SYM_FUNC_END(vmx_vmexit) |
| |
| /** |
| * __vmx_vcpu_run - Run a vCPU via a transition to VMX guest mode |
| * @vmx: struct vcpu_vmx * (forwarded to vmx_update_host_rsp) |
| * @regs: unsigned long * (to guest registers) |
| * @launched: %true if the VMCS has been launched |
| * |
| * 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 @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 @launched to BL, _ASM_ARG3 is volatile. */ |
| mov %_ASM_ARG3B, %bl |
| |
| /* Adjust RSP to account for the CALL to vmx_vmenter(). */ |
| lea -WORD_SIZE(%_ASM_SP), %_ASM_ARG2 |
| call vmx_update_host_rsp |
| |
| /* Load @regs to RAX. */ |
| mov (%_ASM_SP), %_ASM_AX |
| |
| /* Check if vmlaunch or vmresume is needed */ |
| cmpb $0, %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 |
| |
| /* Enter guest mode */ |
| call vmx_vmenter |
| |
| /* Jump on VM-Fail. */ |
| jbe 2f |
| |
| /* 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 RAX to indicate VM-Exit (as opposed to VM-Fail). */ |
| xor %eax, %eax |
| |
| /* |
| * Clear all general purpose registers except RSP and RAX 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 RAX are exempt as RSP is restored by hardware during |
| * VM-Exit and RAX is explicitly loaded with 0 or 1 to return VM-Fail. |
| */ |
| 1: xor %ecx, %ecx |
| xor %edx, %edx |
| xor %ebx, %ebx |
| 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 |
| |
| /* "POP" @regs. */ |
| add $WORD_SIZE, %_ASM_SP |
| 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 |
| |
| /* VM-Fail. Out-of-line to avoid a taken Jcc after VM-Exit. */ |
| 2: mov $1, %eax |
| jmp 1b |
| SYM_FUNC_END(__vmx_vcpu_run) |
| |
| /** |
| * 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 |
| #ifdef CONFIG_X86_64 |
| /* Load @field and @fault to arg1 and arg2 respectively. */ |
| mov 3*WORD_SIZE(%rbp), %_ASM_ARG2 |
| mov 2*WORD_SIZE(%rbp), %_ASM_ARG1 |
| #else |
| /* Parameters are passed on the stack for 32-bit (see asmlinkage). */ |
| push 3*WORD_SIZE(%ebp) |
| push 2*WORD_SIZE(%ebp) |
| #endif |
| |
| call vmread_error |
| |
| #ifndef CONFIG_X86_64 |
| add $8, %esp |
| #endif |
| |
| /* 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) |