From: Josh Poimboeuf jpoimboe@kernel.org
commit bb06650634d3552c0f8557e9d16aa1a408040e28 upstream.
Convert __vmx_vcpu_run()'s 'launched' argument to 'flags', in preparation for doing SPEC_CTRL handling immediately after vmexit, which will need another flag.
This is much easier than adding a fourth argument, because this code supports both 32-bit and 64-bit, and the fourth argument on 32-bit would have to be pushed on the stack.
Note that __vmx_vcpu_run_flags() is called outside of the noinstr critical section because it will soon start calling potentially traceable functions.
Signed-off-by: Josh Poimboeuf jpoimboe@kernel.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Borislav Petkov bp@suse.de Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@canonical.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/vmx/nested.c | 2 +- arch/x86/kvm/vmx/run_flags.h | 7 +++++++ arch/x86/kvm/vmx/vmenter.S | 9 +++++---- arch/x86/kvm/vmx/vmx.c | 17 ++++++++++++++--- arch/x86/kvm/vmx/vmx.h | 5 ++++- 5 files changed, 31 insertions(+), 9 deletions(-) create mode 100644 arch/x86/kvm/vmx/run_flags.h
--- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -3091,7 +3091,7 @@ static int nested_vmx_check_vmentry_hw(s }
vm_fail = __vmx_vcpu_run(vmx, (unsigned long *)&vcpu->arch.regs, - vmx->loaded_vmcs->launched); + __vmx_vcpu_run_flags(vmx));
if (vmx->msr_autoload.host.nr) vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.host.nr); --- /dev/null +++ b/arch/x86/kvm/vmx/run_flags.h @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __KVM_X86_VMX_RUN_FLAGS_H +#define __KVM_X86_VMX_RUN_FLAGS_H + +#define VMX_RUN_VMRESUME (1 << 0) + +#endif /* __KVM_X86_VMX_RUN_FLAGS_H */ --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -5,6 +5,7 @@ #include <asm/kvm_vcpu_regs.h> #include <asm/nospec-branch.h> #include <asm/segment.h> +#include "run_flags.h"
#define WORD_SIZE (BITS_PER_LONG / 8)
@@ -34,7 +35,7 @@ * __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 + * @flags: VMX_RUN_VMRESUME: use VMRESUME instead of VMLAUNCH * * Returns: * 0 on VM-Exit, 1 on VM-Fail @@ -59,7 +60,7 @@ SYM_FUNC_START(__vmx_vcpu_run) */ push %_ASM_ARG2
- /* Copy @launched to BL, _ASM_ARG3 is volatile. */ + /* Copy @flags to BL, _ASM_ARG3 is volatile. */ mov %_ASM_ARG3B, %bl
lea (%_ASM_SP), %_ASM_ARG2 @@ -69,7 +70,7 @@ SYM_FUNC_START(__vmx_vcpu_run) mov (%_ASM_SP), %_ASM_AX
/* Check if vmlaunch or vmresume is needed */ - testb %bl, %bl + testb $VMX_RUN_VMRESUME, %bl
/* Load guest registers. Don't clobber flags. */ mov VCPU_RCX(%_ASM_AX), %_ASM_CX @@ -92,7 +93,7 @@ SYM_FUNC_START(__vmx_vcpu_run) mov VCPU_RAX(%_ASM_AX), %_ASM_AX
/* Check EFLAGS.ZF from 'testb' above */ - je .Lvmlaunch + jz .Lvmlaunch
/* * After a successful VMRESUME/VMLAUNCH, control flow "magically" --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -839,6 +839,16 @@ static bool msr_write_intercepted(struct MSR_IA32_SPEC_CTRL); }
+unsigned int __vmx_vcpu_run_flags(struct vcpu_vmx *vmx) +{ + unsigned int flags = 0; + + if (vmx->loaded_vmcs->launched) + flags |= VMX_RUN_VMRESUME; + + return flags; +} + static void clear_atomic_switch_msr_special(struct vcpu_vmx *vmx, unsigned long entry, unsigned long exit) { @@ -6827,7 +6837,8 @@ static fastpath_t vmx_exit_handlers_fast }
static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, - struct vcpu_vmx *vmx) + struct vcpu_vmx *vmx, + unsigned long flags) { guest_state_enter_irqoff();
@@ -6846,7 +6857,7 @@ static noinstr void vmx_vcpu_enter_exit( native_write_cr2(vcpu->arch.cr2);
vmx->fail = __vmx_vcpu_run(vmx, (unsigned long *)&vcpu->arch.regs, - vmx->loaded_vmcs->launched); + flags);
vcpu->arch.cr2 = native_read_cr2();
@@ -6954,7 +6965,7 @@ static fastpath_t vmx_vcpu_run(struct kv x86_spec_ctrl_set_guest(vmx->spec_ctrl, 0);
/* The actual VMENTER/EXIT is in the .noinstr.text section. */ - vmx_vcpu_enter_exit(vcpu, vmx); + vmx_vcpu_enter_exit(vcpu, vmx, __vmx_vcpu_run_flags(vmx));
/* * We do not use IBRS in the kernel. If this vCPU has used the --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -13,6 +13,7 @@ #include "vmcs.h" #include "vmx_ops.h" #include "cpuid.h" +#include "run_flags.h"
#define MSR_TYPE_R 1 #define MSR_TYPE_W 2 @@ -404,7 +405,9 @@ void vmx_set_virtual_apic_mode(struct kv struct vmx_uret_msr *vmx_find_uret_msr(struct vcpu_vmx *vmx, u32 msr); void pt_update_intercept_for_msr(struct kvm_vcpu *vcpu); void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp); -bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned long *regs, bool launched); +unsigned int __vmx_vcpu_run_flags(struct vcpu_vmx *vmx); +bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned long *regs, + unsigned int flags); int vmx_find_loadstore_msr_slot(struct vmx_msrs *m, u32 msr); void vmx_ept_load_pdptrs(struct kvm_vcpu *vcpu);