[v2,24/29] KVM: VMX: Move vCPU-run code to a proper assembly routine

Message ID	20190124175845.15926-25-sean.j.christopherson@intel.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <kvm-owner@kernel.org> From: Sean Christopherson <sean.j.christopherson@intel.com> To: Paolo Bonzini <pbonzini@redhat.com>, =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com> Cc: kvm@vger.kernel.org, Jim Mattson <jmattson@google.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Subject: [PATCH v2 24/29] KVM: VMX: Move vCPU-run code to a proper assembly routine Date: Thu, 24 Jan 2019 09:58:41 -0800 Message-Id: <20190124175845.15926-25-sean.j.christopherson@intel.com> In-Reply-To: <20190124175845.15926-1-sean.j.christopherson@intel.com> References: <20190124175845.15926-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk
Series	KVM: VMX: Move vCPU-run to proper asm sub-routine \| expand [v2,00/29] KVM: VMX: Move vCPU-run to proper asm sub-routine [v2,01/29] KVM: VMX: Compare only a single byte for VMCS' "launched" in vCPU-run [v2,02/29] KVM: nVMX: Check a single byte for VMCS "launched" in nested early checks [v2,03/29] KVM: VMX: Modify only RSP when creating a placeholder for guest's RCX [v2,04/29] KVM: VMX: Save RSI to an unused output in the vCPU-run asm blob [v2,05/29] KVM: VMX: Manually load RDX in vCPU-run asm blob [v2,06/29] KVM: VMX: Let the compiler save/load RDX during vCPU-run [v2,07/29] KVM: nVMX: Remove a rogue "rax" clobber from nested_vmx_check_vmentry_hw() [v2,08/29] KVM: nVMX: Drop STACK_FRAME_NON_STANDARD from nested_vmx_check_vmentry_hw() [v2,09/29] KVM: nVMX: Explicitly reference the scratch reg in nested early checks [v2,10/29] KVM: nVMX: Capture VM-Fail to a local var in nested_vmx_check_vmentry_hw() [v2,11/29] KVM: nVMX: Capture VM-Fail via CC_{SET,OUT} in nested early checks [v2,12/29] KVM: nVMX: Reference vmx->loaded_vmcs->launched directly [v2,13/29] KVM: nVMX: Let the compiler select the reg for holding HOST_RSP [v2,14/29] KVM: nVMX: Cache host_rsp on a per-VMCS basis [v2,15/29] KVM: VMX: Load/save guest CR2 via C code in __vmx_vcpu_run() [v2,16/29] KVM: VMX: Update VMCS.HOST_RSP via helper C function [v2,17/29] KVM: VMX: Pass "launched" directly to the vCPU-run asm blob [v2,18/29] KVM: VMX: Invert the ordering of saving guest/host scratch reg at VM-Enter [v2,19/29] KVM: VMX: Don't save guest registers after VM-Fail [v2,20/29] KVM: VMX: Use vcpu->arch.regs directly when saving/loading guest state [v2,21/29] KVM: x86: Explicitly #define the VCPU_REGS_* indices [v2,22/29] KVM: VMX: Use #defines in place of immediates in VM-Enter inline asm [v2,23/29] KVM: VMX: Create a stack frame in vCPU-run [v2,24/29] KVM: VMX: Move vCPU-run code to a proper assembly routine [v2,25/29] KVM: VMX: Fold __vmx_vcpu_run() back into vmx_vcpu_run() [v2,26/29] KVM: VMX: Rename ____vmx_vcpu_run() to __vmx_vcpu_run() [v2,27/29] KVM: VMX: Use RAX as the scratch register during vCPU-run [v2,28/29] KVM: VMX: Make the vCPU-run asm routine callable from C [v2,29/29] KVM: VMX: Reorder clearing of registers in the vCPU-run assembly flow

diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S index bcef2c7e9bc4..daeba6dc3722 100644 --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -1,6 +1,33 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include <linux/linkage.h> #include <asm/asm.h> +#include <asm/kvm_vcpu_regs.h> + +#ifdef CONFIG_X86_64 +#define WORD_SIZE 8 +#else +#define WORD_SIZE 4 +#endif + +#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 @@ -55,3 +82,117 @@ ENDPROC(vmx_vmenter) ENTRY(vmx_vmexit) ret ENDPROC(vmx_vmexit) + +/** + * ____vmx_vcpu_run - Run a vCPU via a transition to VMX guest mode + * @vmx: struct vcpu_vmx * + * @regs: unsigned long * (to guest registers) + * %RBX: VMCS launched status (non-zero indicates already launched) + * + * Returns: + * %RBX is 0 on VM-Exit, 1 on VM-Fail + */ +ENTRY(____vmx_vcpu_run) + /* Create a stack frame and save @regs. */ + push %_ASM_BP + mov %_ASM_SP, %_ASM_BP + push %_ASM_ARG2 + + /* 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 RCX. */ + mov (%_ASM_SP), %_ASM_CX + + /* Check if vmlaunch or vmresume is needed */ + cmpb $0, %bl + + /* Load guest registers. Don't clobber flags. */ + mov VCPU_RAX(%_ASM_CX), %_ASM_AX + mov VCPU_RBX(%_ASM_CX), %_ASM_BX + mov VCPU_RDX(%_ASM_CX), %_ASM_DX + mov VCPU_RSI(%_ASM_CX), %_ASM_SI + mov VCPU_RDI(%_ASM_CX), %_ASM_DI + mov VCPU_RBP(%_ASM_CX), %_ASM_BP +#ifdef CONFIG_X86_64 + mov VCPU_R8 (%_ASM_CX), %r8 + mov VCPU_R9 (%_ASM_CX), %r9 + mov VCPU_R10(%_ASM_CX), %r10 + mov VCPU_R11(%_ASM_CX), %r11 + mov VCPU_R12(%_ASM_CX), %r12 + mov VCPU_R13(%_ASM_CX), %r13 + mov VCPU_R14(%_ASM_CX), %r14 + mov VCPU_R15(%_ASM_CX), %r15 +#endif + /* Load guest RCX. This kills the vmx_vcpu pointer! */ + mov VCPU_RCX(%_ASM_CX), %_ASM_CX + + /* Enter guest mode */ + call vmx_vmenter + + /* Jump on VM-Fail. */ + jbe 2f + + /* Temporarily save guest's RCX. */ + push %_ASM_CX + + /* Reload @regs to RCX. */ + mov WORD_SIZE(%_ASM_SP), %_ASM_CX + + /* Save all guest registers, including RCX from the stack */ + mov %_ASM_AX, VCPU_RAX(%_ASM_CX) + mov %_ASM_BX, VCPU_RBX(%_ASM_CX) + __ASM_SIZE(pop) VCPU_RCX(%_ASM_CX) + mov %_ASM_DX, VCPU_RDX(%_ASM_CX) + mov %_ASM_SI, VCPU_RSI(%_ASM_CX) + mov %_ASM_DI, VCPU_RDI(%_ASM_CX) + mov %_ASM_BP, VCPU_RBP(%_ASM_CX) +#ifdef CONFIG_X86_64 + mov %r8, VCPU_R8 (%_ASM_CX) + mov %r9, VCPU_R9 (%_ASM_CX) + mov %r10, VCPU_R10(%_ASM_CX) + mov %r11, VCPU_R11(%_ASM_CX) + mov %r12, VCPU_R12(%_ASM_CX) + mov %r13, VCPU_R13(%_ASM_CX) + mov %r14, VCPU_R14(%_ASM_CX) + mov %r15, VCPU_R15(%_ASM_CX) +#endif + + /* Clear EBX to indicate VM-Exit (as opposed to VM-Fail). */ + xor %ebx, %ebx + + /* + * Clear registers that contain guest values and will not be + * restored to prevent speculative use of the guest's values. + */ +1: +#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 + xor %eax, %eax + xor %edx, %edx + xor %esi, %esi + xor %edi, %edi + + /* "POP" @regs. */ + add $WORD_SIZE, %_ASM_SP + pop %_ASM_BP + ret + + /* VM-Fail. Out-of-line to avoid a taken Jcc after VM-Exit. */ +2: mov $1, %ebx + /* + * RCX holds a guest value and it's not cleared in the common + * exit path as VM-Exit reloads it with the vcpu_vmx pointer. + */ + xor %ecx, %ecx + jmp 1b +ENDPROC(____vmx_vcpu_run) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 49fe2ca548be..76b68492e077 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6370,33 +6370,6 @@ void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) } } -#ifdef CONFIG_X86_64 -#define WORD_SIZE 8 -#else -#define WORD_SIZE 4 -#endif - -#define _WORD_SIZE __stringify(WORD_SIZE) - -#define VCPU_RAX __stringify(__VCPU_REGS_RAX * WORD_SIZE) -#define VCPU_RCX __stringify(__VCPU_REGS_RCX * WORD_SIZE) -#define VCPU_RDX __stringify(__VCPU_REGS_RDX * WORD_SIZE) -#define VCPU_RBX __stringify(__VCPU_REGS_RBX * WORD_SIZE) -/* Intentionally omit %RSP as it's context switched by hardware */ -#define VCPU_RBP __stringify(__VCPU_REGS_RBP * WORD_SIZE) -#define VCPU_RSI __stringify(__VCPU_REGS_RSI * WORD_SIZE) -#define VCPU_RDI __stringify(__VCPU_REGS_RDI * WORD_SIZE) -#ifdef CONFIG_X86_64 -#define VCPU_R8 __stringify(__VCPU_REGS_R8 * WORD_SIZE) -#define VCPU_R9 __stringify(__VCPU_REGS_R9 * WORD_SIZE) -#define VCPU_R10 __stringify(__VCPU_REGS_R10 * WORD_SIZE) -#define VCPU_R11 __stringify(__VCPU_REGS_R11 * WORD_SIZE) -#define VCPU_R12 __stringify(__VCPU_REGS_R12 * WORD_SIZE) -#define VCPU_R13 __stringify(__VCPU_REGS_R13 * WORD_SIZE) -#define VCPU_R14 __stringify(__VCPU_REGS_R14 * WORD_SIZE) -#define VCPU_R15 __stringify(__VCPU_REGS_R15 * WORD_SIZE) -#endif - static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx) { if (static_branch_unlikely(&vmx_l1d_should_flush)) @@ -6406,108 +6379,7 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx) write_cr2(vcpu->arch.cr2); asm( - "push %%" _ASM_BP " \n\t" - "mov %%" _ASM_SP ", %%" _ASM_BP " \n\t" - "push %%" _ASM_ARG2 " \n\t" - - /* Adjust RSP to account for the CALL to vmx_vmenter(). */ - "lea -" _WORD_SIZE "(%%" _ASM_SP "), %%" _ASM_ARG2 " \n\t" - "call vmx_update_host_rsp \n\t" - - /* Load RCX with @regs. */ - "mov (%%" _ASM_SP "), %%" _ASM_CX " \n\t" - - /* Check if vmlaunch or vmresume is needed */ - "cmpb $0, %%bl \n\t" - - /* Load guest registers. Don't clobber flags. */ - "mov " VCPU_RAX "(%%" _ASM_CX "), %%" _ASM_AX " \n\t" - "mov " VCPU_RBX "(%%" _ASM_CX "), %%" _ASM_BX " \n\t" - "mov " VCPU_RDX "(%%" _ASM_CX "), %%" _ASM_DX " \n\t" - "mov " VCPU_RSI "(%%" _ASM_CX "), %%" _ASM_SI " \n\t" - "mov " VCPU_RDI "(%%" _ASM_CX "), %%" _ASM_DI " \n\t" - "mov " VCPU_RBP "(%%" _ASM_CX "), %%" _ASM_BP " \n\t" -#ifdef CONFIG_X86_64 - "mov " VCPU_R8 "(%%" _ASM_CX "), %%r8 \n\t" - "mov " VCPU_R9 "(%%" _ASM_CX "), %%r9 \n\t" - "mov " VCPU_R10 "(%%" _ASM_CX "), %%r10 \n\t" - "mov " VCPU_R11 "(%%" _ASM_CX "), %%r11 \n\t" - "mov " VCPU_R12 "(%%" _ASM_CX "), %%r12 \n\t" - "mov " VCPU_R13 "(%%" _ASM_CX "), %%r13 \n\t" - "mov " VCPU_R14 "(%%" _ASM_CX "), %%r14 \n\t" - "mov " VCPU_R15 "(%%" _ASM_CX "), %%r15 \n\t" -#endif - /* Load guest RCX. This kills the vmx_vcpu pointer! */ - "mov " VCPU_RCX"(%%" _ASM_CX "), %%" _ASM_CX " \n\t" - - /* Enter guest mode */ - "call vmx_vmenter\n\t" - "jbe 2f \n\t" - - /* Temporarily save guest's RCX. */ - "push %%" _ASM_CX " \n\t" - - /* Reload RCX with @regs. */ - "mov " _WORD_SIZE "(%%" _ASM_SP "), %%" _ASM_CX " \n\t" - - /* Save all guest registers, including RCX from the stack */ - "mov %%" _ASM_AX ", " VCPU_RAX "(%%" _ASM_CX ") \n\t" - "mov %%" _ASM_BX ", " VCPU_RBX "(%%" _ASM_CX ") \n\t" - __ASM_SIZE(pop) " " VCPU_RCX "(%%" _ASM_CX ") \n\t" - "mov %%" _ASM_DX ", " VCPU_RDX "(%%" _ASM_CX ") \n\t" - "mov %%" _ASM_SI ", " VCPU_RSI "(%%" _ASM_CX ") \n\t" - "mov %%" _ASM_DI ", " VCPU_RDI "(%%" _ASM_CX ") \n\t" - "mov %%" _ASM_BP ", " VCPU_RBP "(%%" _ASM_CX ") \n\t" -#ifdef CONFIG_X86_64 - "mov %%r8, " VCPU_R8 "(%%" _ASM_CX ") \n\t" - "mov %%r9, " VCPU_R9 "(%%" _ASM_CX ") \n\t" - "mov %%r10, " VCPU_R10 "(%%" _ASM_CX ") \n\t" - "mov %%r11, " VCPU_R11 "(%%" _ASM_CX ") \n\t" - "mov %%r12, " VCPU_R12 "(%%" _ASM_CX ") \n\t" - "mov %%r13, " VCPU_R13 "(%%" _ASM_CX ") \n\t" - "mov %%r14, " VCPU_R14 "(%%" _ASM_CX ") \n\t" - "mov %%r15, " VCPU_R15 "(%%" _ASM_CX ") \n\t" -#endif - - /* Clear EBX to indicate VM-Exit (as opposed to VM-Fail). */ - "xor %%ebx, %%ebx \n\t" - - /* - * Clear registers that contain guest values and will not be - * restored to prevent speculative use of the guest's values. - */ - "1: \n\t" -#ifdef CONFIG_X86_64 - "xor %%r8d, %%r8d \n\t" - "xor %%r9d, %%r9d \n\t" - "xor %%r10d, %%r10d \n\t" - "xor %%r11d, %%r11d \n\t" - "xor %%r12d, %%r12d \n\t" - "xor %%r13d, %%r13d \n\t" - "xor %%r14d, %%r14d \n\t" - "xor %%r15d, %%r15d \n\t" -#endif - "xor %%eax, %%eax \n\t" - "xor %%edx, %%edx \n\t" - "xor %%esi, %%esi \n\t" - "xor %%edi, %%edi \n\t" - - /* "POP" the vcpu_vmx pointer. */ - "add $" _WORD_SIZE ", %%" _ASM_SP " \n\t" - "pop %%" _ASM_BP " \n\t" - "jmp 3f \n\t" - - /* VM-Fail. Out-of-line to avoid a taken Jcc after VM-Exit. */ - "2: \n\t" - "mov $1, %%ebx \n\t" - /* - * RCX holds a guest value and it's not cleared in the common - * exit path as VM-Exit reloads it with the vcpu_vmx pointer. - */ - "xor %%ecx, %%ecx \n\t" - "jmp 1b \n\t" - "3: \n\t" - + "call ____vmx_vcpu_run \n\t" : ASM_CALL_CONSTRAINT, "=b"(vmx->fail), #ifdef CONFIG_X86_64 "=D"((int){0}), "=S"((int){0}) @@ -6528,7 +6400,6 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx) vcpu->arch.cr2 = read_cr2(); } -STACK_FRAME_NON_STANDARD(__vmx_vcpu_run); static void vmx_vcpu_run(struct kvm_vcpu *vcpu) {

[v2,24/29] KVM: VMX: Move vCPU-run code to a proper assembly routine

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