Fix fault injection in bhyve.
The faulting instruction needs to be restarted when the exception handler is done handling the fault. bhyve now does this correctly by setting 'vmexit[vcpu].inst_length' to zero so the %rip is not advanced. A minor complication is that the fault injection APIs are used by instruction emulation code that is shared by vmm.ko and bhyve. Thus the argument that refers to 'struct vm *' in kernel or 'struct vmctx *' in userspace needs to be loosely typed as a 'void *'.
This commit is contained in:
parent
31a01497f2
commit
d37f2adb38
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=269042
@ -1146,30 +1146,3 @@ vm_set_intinfo(struct vmctx *ctx, int vcpu, uint64_t info1)
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error = ioctl(ctx->fd, VM_SET_INTINFO, &vmii);
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return (error);
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}
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void
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vm_inject_ss(struct vmctx *ctx, int vcpu, int errcode)
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{
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int error;
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error = vm_inject_exception2(ctx, vcpu, IDT_SS, errcode);
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assert(error == 0);
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}
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void
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vm_inject_ac(struct vmctx *ctx, int vcpu, int errcode)
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{
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int error;
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error = vm_inject_exception2(ctx, vcpu, IDT_AC, errcode);
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assert(error == 0);
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}
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void
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vm_inject_gp(struct vmctx *ctx, int vcpu, int errcode)
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{
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int error;
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error = vm_inject_exception2(ctx, vcpu, IDT_GP, errcode);
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assert(error == 0);
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}
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@ -133,11 +133,6 @@ void vm_copyin(struct vmctx *ctx, int vcpu, struct iovec *guest_iov,
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void vm_copyout(struct vmctx *ctx, int vcpu, const void *host_src,
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struct iovec *guest_iov, size_t len);
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/* Helper functions to inject exceptions */
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void vm_inject_ss(struct vmctx *ctx, int vcpu, int errcode);
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void vm_inject_ac(struct vmctx *ctx, int vcpu, int errcode);
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void vm_inject_gp(struct vmctx *ctx, int vcpu, int errcode);
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/* Reset vcpu register state */
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int vcpu_reset(struct vmctx *ctx, int vcpu);
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@ -29,6 +29,8 @@
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#ifndef _VMM_H_
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#define _VMM_H_
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#include <x86/segments.h>
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enum vm_suspend_how {
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VM_SUSPEND_NONE,
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VM_SUSPEND_RESET,
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@ -316,12 +318,6 @@ int vm_entry_intinfo(struct vm *vm, int vcpuid, uint64_t *info);
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int vm_get_intinfo(struct vm *vm, int vcpuid, uint64_t *info1, uint64_t *info2);
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void vm_inject_gp(struct vm *vm, int vcpuid); /* general protection fault */
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void vm_inject_ud(struct vm *vm, int vcpuid); /* undefined instruction fault */
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void vm_inject_ac(struct vm *vm, int vcpuid, int errcode); /* #AC */
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void vm_inject_ss(struct vm *vm, int vcpuid, int errcode); /* #SS */
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void vm_inject_pf(struct vm *vm, int vcpuid, int error_code, uint64_t cr2);
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enum vm_reg_name vm_segment_name(int seg_encoding);
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struct vm_copyinfo {
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@ -579,4 +575,34 @@ struct vm_exit {
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} u;
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};
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/* APIs to inject faults into the guest */
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void vm_inject_fault(void *vm, int vcpuid, int vector, int errcode_valid,
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int errcode);
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static void __inline
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vm_inject_ud(void *vm, int vcpuid)
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{
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vm_inject_fault(vm, vcpuid, IDT_UD, 0, 0);
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}
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static void __inline
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vm_inject_gp(void *vm, int vcpuid)
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{
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vm_inject_fault(vm, vcpuid, IDT_GP, 1, 0);
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}
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static void __inline
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vm_inject_ac(void *vm, int vcpuid, int errcode)
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{
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vm_inject_fault(vm, vcpuid, IDT_AC, 1, errcode);
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}
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static void __inline
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vm_inject_ss(void *vm, int vcpuid, int errcode)
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{
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vm_inject_fault(vm, vcpuid, IDT_SS, 1, errcode);
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}
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void vm_inject_pf(void *vm, int vcpuid, int error_code, uint64_t cr2);
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#endif /* _VMM_H_ */
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@ -1689,13 +1689,21 @@ vm_inject_exception(struct vm *vm, int vcpuid, struct vm_exception *exception)
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return (0);
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}
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static void
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vm_inject_fault(struct vm *vm, int vcpuid, struct vm_exception *exception)
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void
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vm_inject_fault(void *vmarg, int vcpuid, int vector, int errcode_valid,
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int errcode)
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{
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struct vm_exception exception;
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struct vm_exit *vmexit;
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struct vm *vm;
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int error;
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error = vm_inject_exception(vm, vcpuid, exception);
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vm = vmarg;
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exception.vector = vector;
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exception.error_code = errcode;
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exception.error_code_valid = errcode_valid;
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error = vm_inject_exception(vm, vcpuid, &exception);
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KASSERT(error == 0, ("vm_inject_exception error %d", error));
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/*
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@ -1710,69 +1718,19 @@ vm_inject_fault(struct vm *vm, int vcpuid, struct vm_exception *exception)
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}
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void
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vm_inject_pf(struct vm *vm, int vcpuid, int error_code, uint64_t cr2)
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vm_inject_pf(void *vmarg, int vcpuid, int error_code, uint64_t cr2)
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{
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struct vm_exception pf = {
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.vector = IDT_PF,
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.error_code_valid = 1,
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.error_code = error_code
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};
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struct vm *vm;
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int error;
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vm = vmarg;
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VCPU_CTR2(vm, vcpuid, "Injecting page fault: error_code %#x, cr2 %#lx",
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error_code, cr2);
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error = vm_set_register(vm, vcpuid, VM_REG_GUEST_CR2, cr2);
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KASSERT(error == 0, ("vm_set_register(cr2) error %d", error));
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vm_inject_fault(vm, vcpuid, &pf);
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}
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void
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vm_inject_gp(struct vm *vm, int vcpuid)
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{
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struct vm_exception gpf = {
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.vector = IDT_GP,
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.error_code_valid = 1,
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.error_code = 0
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};
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vm_inject_fault(vm, vcpuid, &gpf);
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}
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void
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vm_inject_ud(struct vm *vm, int vcpuid)
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{
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struct vm_exception udf = {
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.vector = IDT_UD,
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.error_code_valid = 0
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};
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vm_inject_fault(vm, vcpuid, &udf);
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}
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void
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vm_inject_ac(struct vm *vm, int vcpuid, int error_code)
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{
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struct vm_exception acf = {
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.vector = IDT_AC,
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.error_code_valid = 1,
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.error_code = error_code
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};
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vm_inject_fault(vm, vcpuid, &acf);
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}
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void
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vm_inject_ss(struct vm *vm, int vcpuid, int error_code)
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{
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struct vm_exception ssf = {
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.vector = IDT_SS,
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.error_code_valid = 1,
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.error_code = error_code
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};
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vm_inject_fault(vm, vcpuid, &ssf);
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vm_inject_fault(vm, vcpuid, IDT_PF, 1, error_code);
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}
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static VMM_STAT(VCPU_NMI_COUNT, "number of NMIs delivered to vcpu");
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@ -96,7 +96,7 @@ static cpuset_t cpumask;
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static void vm_loop(struct vmctx *ctx, int vcpu, uint64_t rip);
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struct vm_exit vmexit[VM_MAXCPU];
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static struct vm_exit vmexit[VM_MAXCPU];
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struct bhyvestats {
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uint64_t vmexit_bogus;
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@ -182,6 +182,27 @@ pincpu_parse(const char *opt)
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return (0);
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}
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void
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vm_inject_fault(void *arg, int vcpu, int vector, int errcode_valid,
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int errcode)
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{
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struct vmctx *ctx;
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int error;
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ctx = arg;
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if (errcode_valid)
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error = vm_inject_exception2(ctx, vcpu, vector, errcode);
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else
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error = vm_inject_exception(ctx, vcpu, vector);
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assert(error == 0);
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/*
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* Set the instruction length to 0 to ensure that the instruction is
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* restarted when the fault handler returns.
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*/
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vmexit[vcpu].inst_length = 0;
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}
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void *
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paddr_guest2host(struct vmctx *ctx, uintptr_t gaddr, size_t len)
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{
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@ -347,7 +368,7 @@ vmexit_rdmsr(struct vmctx *ctx, struct vm_exit *vme, int *pvcpu)
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fprintf(stderr, "rdmsr to register %#x on vcpu %d\n",
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vme->u.msr.code, *pvcpu);
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if (strictmsr) {
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vm_inject_gp(ctx, *pvcpu, 0);
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vm_inject_gp(ctx, *pvcpu);
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return (VMEXIT_RESTART);
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}
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}
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@ -373,7 +394,7 @@ vmexit_wrmsr(struct vmctx *ctx, struct vm_exit *vme, int *pvcpu)
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fprintf(stderr, "wrmsr to register %#x(%#lx) on vcpu %d\n",
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vme->u.msr.code, vme->u.msr.wval, *pvcpu);
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if (strictmsr) {
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vm_inject_gp(ctx, *pvcpu, 0);
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vm_inject_gp(ctx, *pvcpu);
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return (VMEXIT_RESTART);
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}
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}
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@ -157,7 +157,7 @@ emulate_inout(struct vmctx *ctx, int vcpu, struct vm_exit *vmexit, int strict)
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if (vie_calculate_gla(vis->paging.cpu_mode,
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vis->seg_name, &vis->seg_desc, index, bytes,
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addrsize, prot, &gla)) {
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vm_inject_gp(ctx, vcpu, 0);
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vm_inject_gp(ctx, vcpu);
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retval = INOUT_RESTART;
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break;
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}
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@ -160,8 +160,6 @@ usd_to_seg_desc(struct user_segment_descriptor *usd)
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static void
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sel_exception(struct vmctx *ctx, int vcpu, int vector, uint16_t sel, int ext)
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{
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int error;
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/*
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* Bit 2 from the selector is retained as-is in the error code.
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*
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@ -174,8 +172,7 @@ sel_exception(struct vmctx *ctx, int vcpu, int vector, uint16_t sel, int ext)
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sel &= ~0x3;
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if (ext)
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sel |= 0x1;
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error = vm_inject_exception2(ctx, vcpu, vector, sel);
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assert(error == 0);
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vm_inject_fault(ctx, vcpu, vector, 1, sel);
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}
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static int
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@ -508,7 +505,7 @@ tss32_restore(struct vmctx *ctx, int vcpu, struct vm_task_switch *ts,
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*/
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reserved = ~maxphyaddr | 0x1E6;
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if (pdpte[i] & reserved) {
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vm_inject_gp(ctx, vcpu, 0);
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vm_inject_gp(ctx, vcpu);
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return (VMEXIT_RESTART);
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}
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}
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