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Fix SVM handling of ASTPENDING, which manifested as a

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hang on console output (due to a missing interrupt).

SVM does exit processing and then handles ASTPENDING which
overwrites the already handled SVM exit cause and corrupts
virtual machine state. For example, if the SVM exit was due to
an I/O port access but the main loop detected an ASTPENDING,
the exit would be processed as ASTPENDING and leave the
device (e.g. emulated UART) for that I/O port in bad state.

Submitted by:	Anish Gupta (akgupt3@gmail.com)
Reviewed by:	grehan
This commit is contained in:
Peter Grehan 2013-10-16 05:43:03 +00:00
parent 21b770fcad
commit 4599af439f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/projects/bhyve_svm/; revision=256588
1 changed files with 21 additions and 11 deletions
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32
sys/amd64/vmm/amd/svm.c
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@ -678,6 +678,8 @@ svm_vmexit(struct svm_softc *svm_sc, int vcpu, struct vm_exit *vmexit)
case VMCB_EXIT_IO: case VMCB_EXIT_IO:
vmm_stat_incr(svm_sc->vm, vcpu, VMEXIT_INOUT, 1); vmm_stat_incr(svm_sc->vm, vcpu, VMEXIT_INOUT, 1);
user = svm_handle_io(svm_sc, vcpu, vmexit); user = svm_handle_io(svm_sc, vcpu, vmexit);
VMM_CTR1(svm_sc->vm, vcpu, "SVM:I/O VMEXIT RIP:0x%lx\n",
state->rip);
break; break;
case VMCB_EXIT_CPUID: case VMCB_EXIT_CPUID:
@ -691,7 +693,7 @@ svm_vmexit(struct svm_softc *svm_sc, int vcpu, struct vm_exit *vmexit)
user = 0; user = 0;
break; break;
case VMCB_EXIT_HLT: case VMCB_EXIT_HLT:
vmm_stat_incr(svm_sc->vm, vcpu, VMEXIT_HLT, 1); vmm_stat_incr(svm_sc->vm, vcpu, VMEXIT_HLT, 1);
if (ctrl->v_irq) { if (ctrl->v_irq) {
/* Interrupt is pending, can't halt guest. */ /* Interrupt is pending, can't halt guest. */
@ -709,7 +711,7 @@ svm_vmexit(struct svm_softc *svm_sc, int vcpu, struct vm_exit *vmexit)
} }
break; break;
case VMCB_EXIT_PAUSE: case VMCB_EXIT_PAUSE:
VMM_CTR0(svm_sc->vm, vcpu, "SVM:VMEXIT pause"); VMM_CTR0(svm_sc->vm, vcpu, "SVM:VMEXIT pause");
vmexit->exitcode = VM_EXITCODE_PAUSE; vmexit->exitcode = VM_EXITCODE_PAUSE;
vmm_stat_incr(svm_sc->vm, vcpu, VMEXIT_PAUSE, 1); vmm_stat_incr(svm_sc->vm, vcpu, VMEXIT_PAUSE, 1);
@ -975,7 +977,19 @@ svm_vmrun(void *arg, int vcpu, register_t rip)
/* Update Guest RIP */ /* Update Guest RIP */
state->rip = rip; state->rip = rip;
VMM_CTR1(svm_sc->vm, vcpu, "SVM:entered with RIP:0x%lx\n",
state->rip);
do { do {
/* We are asked to give the cpu by scheduler. */
if (curthread->td_flags & (TDF_ASTPENDING | TDF_NEEDRESCHED)) {
vmexit->exitcode = VM_EXITCODE_BOGUS;
vmexit->inst_length = 0;
vmm_stat_incr(svm_sc->vm, vcpu, VMEXIT_ASTPENDING, 1);
VMM_CTR1(svm_sc->vm, vcpu, "SVM:gave up cpu, RIP:0x%lx\n",
state->rip);
break;
}
lapic_timer_tick(svm_sc->vm, vcpu); lapic_timer_tick(svm_sc->vm, vcpu);
(void)svm_set_vmcb(svm_get_vmcb(svm_sc, vcpu), svm_sc->asid); (void)svm_set_vmcb(svm_get_vmcb(svm_sc, vcpu), svm_sc->asid);
@ -1022,7 +1036,6 @@ svm_vmrun(void *arg, int vcpu, register_t rip)
wrmsr(MSR_GSBASE, (uint64_t)&__pcpu[vcpustate->lastcpu]); wrmsr(MSR_GSBASE, (uint64_t)&__pcpu[vcpustate->lastcpu]);
wrmsr(MSR_KGSBASE, (uint64_t)&__pcpu[vcpustate->lastcpu]); wrmsr(MSR_KGSBASE, (uint64_t)&__pcpu[vcpustate->lastcpu]);
/* vcpu exit with glbal interrupt disabled. */ /* vcpu exit with glbal interrupt disabled. */
enable_gintr(); enable_gintr();
@ -1031,16 +1044,13 @@ svm_vmrun(void *arg, int vcpu, register_t rip)
vcpustate->loop++; vcpustate->loop++;
vmm_stat_incr(svm_sc->vm, vcpu, VMEXIT_COUNT, 1); vmm_stat_incr(svm_sc->vm, vcpu, VMEXIT_COUNT, 1);
/* We are asked to give the cpud by scheduler.*/
if (curthread->td_flags & (TDF_ASTPENDING | TDF_NEEDRESCHED)) {
vmexit->exitcode = VM_EXITCODE_BOGUS;
vmexit->inst_length = 0;
break;
}
/* Update RIP since we are continuing vcpu execution.*/ /* Update RIP since we are continuing vcpu execution.*/
state->rip = vmexit->rip; state->rip = vmexit->rip;
VMM_CTR1(svm_sc->vm, vcpu, "SVM:loop RIP:0x%lx\n", state->rip);
} while (!user); } while (!user);
VMM_CTR1(svm_sc->vm, vcpu, "SVM:exited with RIP:0x%lx\n",
state->rip);
return (0); return (0);
} }
@ -1260,7 +1270,7 @@ svm_setcap(void *arg, int vcpu, int type, int val)
ctrl = svm_get_vmcb_ctrl(svm_sc, vcpu); ctrl = svm_get_vmcb_ctrl(svm_sc, vcpu);
switch (type) { switch (type) {
case VM_CAP_HALT_EXIT: case VM_CAP_HALT_EXIT:
if (val) if (val)
ctrl->ctrl1 |= VMCB_INTCPT_HLT; ctrl->ctrl1 |= VMCB_INTCPT_HLT;
else else