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Differential D26003 Diff 75592 sys/amd64/vmm/intel/vmx.c

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sys/amd64/vmm/intel/vmx.c

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static int cap_halt_exit; static int cap_halt_exit;
SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, halt_exit, CTLFLAG_RD, &cap_halt_exit, 0, SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, halt_exit, CTLFLAG_RD, &cap_halt_exit, 0,
"HLT triggers a VM-exit"); "HLT triggers a VM-exit");
static int cap_pause_exit; static int cap_pause_exit;
SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, pause_exit, CTLFLAG_RD, &cap_pause_exit, SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, pause_exit, CTLFLAG_RD, &cap_pause_exit,
0, "PAUSE triggers a VM-exit"); 0, "PAUSE triggers a VM-exit");
static int cap_rdpid;
SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, rdpid, CTLFLAG_RD, &cap_rdpid, 0,
"Guests are allowed to use RDPID");
static int cap_rdtscp;
SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, rdtscp, CTLFLAG_RD, &cap_rdtscp, 0,
"Guests are allowed to use RDTSCP");
static int cap_unrestricted_guest; static int cap_unrestricted_guest;
SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, unrestricted_guest, CTLFLAG_RD, SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, unrestricted_guest, CTLFLAG_RD,
&cap_unrestricted_guest, 0, "Unrestricted guests"); &cap_unrestricted_guest, 0, "Unrestricted guests");
static int cap_monitor_trap; static int cap_monitor_trap;
SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, monitor_trap, CTLFLAG_RD, SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, monitor_trap, CTLFLAG_RD,
&cap_monitor_trap, 0, "Monitor trap flag"); &cap_monitor_trap, 0, "Monitor trap flag");
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static int vmx_getdesc(void *arg, int vcpu, int reg, struct seg_desc *desc); static int vmx_getdesc(void *arg, int vcpu, int reg, struct seg_desc *desc);
static int vmx_getreg(void *arg, int vcpu, int reg, uint64_t *retval); static int vmx_getreg(void *arg, int vcpu, int reg, uint64_t *retval);
static int vmxctx_setreg(struct vmxctx *vmxctx, int reg, uint64_t val); static int vmxctx_setreg(struct vmxctx *vmxctx, int reg, uint64_t val);
static void vmx_inject_pir(struct vlapic *vlapic); static void vmx_inject_pir(struct vlapic *vlapic);
#ifdef BHYVE_SNAPSHOT #ifdef BHYVE_SNAPSHOT
static int vmx_restore_tsc(void *arg, int vcpu, uint64_t now); static int vmx_restore_tsc(void *arg, int vcpu, uint64_t now);
#endif #endif
static inline bool
host_has_rdpid(void)
{
return ((cpu_stdext_feature2 & CPUID_STDEXT2_RDPID) != 0);
}
static inline bool
host_has_rdtscp(void)
{
return ((amd_feature & AMDID_RDTSCP) != 0);
}
#ifdef KTR #ifdef KTR
static const char * static const char *
exit_reason_to_str(int reason) exit_reason_to_str(int reason)
{ {
static char reasonbuf[32]; static char reasonbuf[32];
switch (reason) { switch (reason) {
case EXIT_REASON_EXCEPTION: case EXIT_REASON_EXCEPTION:
▲ Show 20 Lines • Show All 436 Lines • ▼ Show 20 Lines cap_monitor_trap = (vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS,
PROCBASED_MTF, 0, PROCBASED_MTF, 0,
&tmp) == 0); &tmp) == 0);
cap_pause_exit = (vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS, cap_pause_exit = (vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS,
MSR_VMX_TRUE_PROCBASED_CTLS, MSR_VMX_TRUE_PROCBASED_CTLS,
PROCBASED_PAUSE_EXITING, 0, PROCBASED_PAUSE_EXITING, 0,
&tmp) == 0); &tmp) == 0);
/*
* Check support for RDPID and/or RDTSCP.
*
* Support a pass-through-based implementation of these via the
* "enable RDTSCP" VM-execution control and the "RDTSC exiting"
* VM-execution control.
*
* The "enable RDTSCP" VM-execution control applies to both RDPID
* and RDTSCP (see SDM volume 3, section 25.3, "Changes to
* Instruction Behavior in VMX Non-root operation"); this is why
* only this VM-execution control needs to be enabled in order to
* enable passing through whichever of RDPID and/or RDTSCP are
* supported by the host.
*
* The "RDTSC exiting" VM-execution control applies to both RDTSC
* and RDTSCP (again, per SDM volume 3, section 25.3), and is
* already set up for RDTSC and RDTSCP pass-through by the current
* implementation of RDTSC.
*
* Although RDPID and RDTSCP are optional capabilities, since there
* does not currently seem to be a use case for enabling/disabling
* these via libvmmapi, choose not to support this and, instead,
* just statically always enable or always disable this support
* across all vCPUs on all VMs. (Note that there may be some
* complications to providing this functionality, e.g., the MSR
* bitmap is currently per-VM rather than per-vCPU while the
* capability API wants to be able to control capabilities on a
* per-vCPU basis).
*/
error = vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS2,
MSR_VMX_PROCBASED_CTLS2,
PROCBASED2_ENABLE_RDTSCP, 0, &tmp);
cap_rdpid = error == 0 && host_has_rdpid();
cap_rdtscp = error == 0 && host_has_rdtscp();
if (cap_rdpid || cap_rdtscp)
procbased_ctls2 |= PROCBASED2_ENABLE_RDTSCP;
cap_unrestricted_guest = (vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS2, cap_unrestricted_guest = (vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS2,
MSR_VMX_PROCBASED_CTLS2, MSR_VMX_PROCBASED_CTLS2,
PROCBASED2_UNRESTRICTED_GUEST, 0, PROCBASED2_UNRESTRICTED_GUEST, 0,
&tmp) == 0); &tmp) == 0);
cap_invpcid = (vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS2, cap_invpcid = (vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS2,
MSR_VMX_PROCBASED_CTLS2, PROCBASED2_ENABLE_INVPCID, 0, MSR_VMX_PROCBASED_CTLS2, PROCBASED2_ENABLE_INVPCID, 0,
&tmp) == 0); &tmp) == 0);
▲ Show 20 Lines • Show All 236 Lines • ▼ Show 20 Linesvmx_vminit(struct vm *vm, pmap_t pmap)
* VM exit and entry respectively. It is also restored from the * VM exit and entry respectively. It is also restored from the
* host VMCS area on a VM exit. * host VMCS area on a VM exit.
* *
* The TSC MSR is exposed read-only. Writes are disallowed as * The TSC MSR is exposed read-only. Writes are disallowed as
* that will impact the host TSC. If the guest does a write * that will impact the host TSC. If the guest does a write
* the "use TSC offsetting" execution control is enabled and the * the "use TSC offsetting" execution control is enabled and the
* difference between the host TSC and the guest TSC is written * difference between the host TSC and the guest TSC is written
* into the TSC offset in the VMCS. * into the TSC offset in the VMCS.
*
* Guest TSC_AUX support is enabled if any of guest RDPID and/or
* guest RDTSCP support are enabled (since, as per Table 2-2 in SDM
* volume 4, TSC_AUX is supported if any of RDPID and/or RDTSCP are
* supported). If guest TSC_AUX support is enabled, TSC_AUX is
* exposed read-only so that the VMM can do one fewer MSR read per
* exit than if this register were exposed read-write; the guest
* restore value can be updated during guest writes (expected to be
* rare) instead of during all exits (common).
*/ */
if (guest_msr_rw(vmx, MSR_GSBASE) || if (guest_msr_rw(vmx, MSR_GSBASE) ||
guest_msr_rw(vmx, MSR_FSBASE) || guest_msr_rw(vmx, MSR_FSBASE) ||
guest_msr_rw(vmx, MSR_SYSENTER_CS_MSR) || guest_msr_rw(vmx, MSR_SYSENTER_CS_MSR) ||
guest_msr_rw(vmx, MSR_SYSENTER_ESP_MSR) || guest_msr_rw(vmx, MSR_SYSENTER_ESP_MSR) ||
guest_msr_rw(vmx, MSR_SYSENTER_EIP_MSR) || guest_msr_rw(vmx, MSR_SYSENTER_EIP_MSR) ||
guest_msr_rw(vmx, MSR_EFER) || guest_msr_rw(vmx, MSR_EFER) ||
guest_msr_ro(vmx, MSR_TSC)) guest_msr_ro(vmx, MSR_TSC) ||
((cap_rdpid || cap_rdtscp) && guest_msr_ro(vmx, MSR_TSC_AUX)))
panic("vmx_vminit: error setting guest msr access"); panic("vmx_vminit: error setting guest msr access");
vpid_alloc(vpid, VM_MAXCPU); vpid_alloc(vpid, VM_MAXCPU);
if (virtual_interrupt_delivery) { if (virtual_interrupt_delivery) {
error = vm_map_mmio(vm, DEFAULT_APIC_BASE, PAGE_SIZE, error = vm_map_mmio(vm, DEFAULT_APIC_BASE, PAGE_SIZE,
APIC_ACCESS_ADDRESS); APIC_ACCESS_ADDRESS);
/* XXX this should really return an error to the caller */ /* XXX this should really return an error to the caller */
▲ Show 20 Lines • Show All 62 Lines • ▼ Show 20 Lines if (posted_interrupts) {
error += vmwrite(VMCS_PIR_VECTOR, pirvec); error += vmwrite(VMCS_PIR_VECTOR, pirvec);
error += vmwrite(VMCS_PIR_DESC, error += vmwrite(VMCS_PIR_DESC,
vtophys(&vmx->pir_desc[i])); vtophys(&vmx->pir_desc[i]));
} }
VMCLEAR(vmcs); VMCLEAR(vmcs);
KASSERT(error == 0, ("vmx_vminit: error customizing the vmcs")); KASSERT(error == 0, ("vmx_vminit: error customizing the vmcs"));
vmx->cap[i].set = 0; vmx->cap[i].set = 0;
vmx->cap[i].set |= cap_rdpid != 0 ? 1 << VM_CAP_RDPID : 0;
vmx->cap[i].set |= cap_rdtscp != 0 ? 1 << VM_CAP_RDTSCP : 0;
vmx->cap[i].proc_ctls = procbased_ctls; vmx->cap[i].proc_ctls = procbased_ctls;
vmx->cap[i].proc_ctls2 = procbased_ctls2; vmx->cap[i].proc_ctls2 = procbased_ctls2;
vmx->cap[i].exc_bitmap = exc_bitmap; vmx->cap[i].exc_bitmap = exc_bitmap;
vmx->state[i].nextrip = ~0; vmx->state[i].nextrip = ~0;
vmx->state[i].lastcpu = NOCPU; vmx->state[i].lastcpu = NOCPU;
vmx->state[i].vpid = vpid[i]; vmx->state[i].vpid = vpid[i];
▲ Show 20 Lines • Show All 1,895 Lines • ▼ Show 20 Lines do {
* LDT, but save and restore it to be safe. * LDT, but save and restore it to be safe.
*/ */
sgdt(&gdtr); sgdt(&gdtr);
sidt(&idtr); sidt(&idtr);
ldt_sel = sldt(); ldt_sel = sldt();
vmx_run_trace(vmx, vcpu); vmx_run_trace(vmx, vcpu);
vmx_dr_enter_guest(vmxctx); vmx_dr_enter_guest(vmxctx);
/*
* The TSC_AUX MSR must be saved/restored while interrupts
* are disabled so that it is not possible for the guest
* TSC_AUX MSR value to be overwritten by the resume
* portion of the IPI_SUSPEND codepath. This is why the
* transition of this MSR is handled separately from those
* handled by vmx_msr_guest_{enter,exit}(), which are ok to
* be transitioned with preemption disabled but interrupts
* enabled.
*
* These vmx_msr_guest_{enter,exit}_tsc_aux() calls can be
* anywhere in this loop so long as they happen with
* interrupts disabled. This location is chosen for
* simplicity.
*/
vmx_msr_guest_enter_tsc_aux(vmx, vcpu);
grehanUnsubmitted
Done
Inline Actions

I'm still undecided as to whether the debug register save/restore should be closer to the enter_guest call than the tsx_aux save/restore. jhb, any thoughts ?

grehan: I'm still undecided as to whether the debug register save/restore should be closer to the…
jhbUnsubmitted
Done
Inline Actions

I'm still undecided as to whether the debug register save/restore should be closer to the enter_guest call than the tsx_aux save/restore. jhb, any thoughts ?

Hmmm, I think the only argument for doing it before debug is that it means in theory you could use DDB to single step through vmx_guest_enter_tsc_aux(). In practice I'm not sure it really matters all that much? I think though I might lean towards doing the tsc_aux save/restore "outside" of the debug registers. I would perhaps even do the save before vmx_run_trace().

jhb: > I'm still undecided as to whether the debug register save/restore should be closer to the…
rc = vmx_enter_guest(vmxctx, vmx, launched); rc = vmx_enter_guest(vmxctx, vmx, launched);
vmx_msr_guest_exit_tsc_aux(vmx, vcpu);
vmx_dr_leave_guest(vmxctx); vmx_dr_leave_guest(vmxctx);
bare_lgdt(&gdtr); bare_lgdt(&gdtr);
lidt(&idtr); lidt(&idtr);
lldt(ldt_sel); lldt(ldt_sel);
/* Collect some information for VM exit processing */ /* Collect some information for VM exit processing */
vmexit->rip = rip = vmcs_guest_rip(); vmexit->rip = rip = vmcs_guest_rip();
▲ Show 20 Lines • Show All 323 Lines • ▼ Show 20 Linesvmx_getcap(void *arg, int vcpu, int type, int *retval)
case VM_CAP_PAUSE_EXIT: case VM_CAP_PAUSE_EXIT:
if (cap_pause_exit) if (cap_pause_exit)
ret = 0; ret = 0;
break; break;
case VM_CAP_MTRAP_EXIT: case VM_CAP_MTRAP_EXIT:
if (cap_monitor_trap) if (cap_monitor_trap)
ret = 0; ret = 0;
break; break;
case VM_CAP_RDPID:
if (cap_rdpid)
ret = 0;
break;
case VM_CAP_RDTSCP:
if (cap_rdtscp)
ret = 0;
break;
case VM_CAP_UNRESTRICTED_GUEST: case VM_CAP_UNRESTRICTED_GUEST:
if (cap_unrestricted_guest) if (cap_unrestricted_guest)
ret = 0; ret = 0;
break; break;
case VM_CAP_ENABLE_INVPCID: case VM_CAP_ENABLE_INVPCID:
if (cap_invpcid) if (cap_invpcid)
ret = 0; ret = 0;
break; break;
▲ Show 20 Lines • Show All 47 Lines • ▼ Show 20 Linesvmx_setcap(void *arg, int vcpu, int type, int val)
case VM_CAP_PAUSE_EXIT: case VM_CAP_PAUSE_EXIT:
if (cap_pause_exit) { if (cap_pause_exit) {
retval = 0; retval = 0;
pptr = &vmx->cap[vcpu].proc_ctls; pptr = &vmx->cap[vcpu].proc_ctls;
baseval = *pptr; baseval = *pptr;
flag = PROCBASED_PAUSE_EXITING; flag = PROCBASED_PAUSE_EXITING;
reg = VMCS_PRI_PROC_BASED_CTLS; reg = VMCS_PRI_PROC_BASED_CTLS;
} }
break;
case VM_CAP_RDPID:
case VM_CAP_RDTSCP:
if (cap_rdpid || cap_rdtscp)
/*
* Choose not to support enabling/disabling
* RDPID/RDTSCP via libvmmapi since, as per the
* discussion in vmx_init(), RDPID/RDTSCP are
* either always enabled or always disabled.
*/
error = EOPNOTSUPP;
break; break;
case VM_CAP_UNRESTRICTED_GUEST: case VM_CAP_UNRESTRICTED_GUEST:
if (cap_unrestricted_guest) { if (cap_unrestricted_guest) {
retval = 0; retval = 0;
pptr = &vmx->cap[vcpu].proc_ctls2; pptr = &vmx->cap[vcpu].proc_ctls2;
baseval = *pptr; baseval = *pptr;
flag = PROCBASED2_UNRESTRICTED_GUEST; flag = PROCBASED2_UNRESTRICTED_GUEST;
reg = VMCS_SEC_PROC_BASED_CTLS; reg = VMCS_SEC_PROC_BASED_CTLS;
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