MFC 261638,262144,262506,266765:

Add virtualized XSAVE support to bhyve which permits guests to use XSAVE and
XSAVE-enabled features like AVX.
- Store a per-cpu guest xcr0 register and handle xsetbv VM exits by emulating
  the instruction.
- Only expose XSAVE to guests if XSAVE is enabled in the host.  Only expose
  a subset of XSAVE features currently supported by the guest and for which
  the proper emulation of xsetbv is known.  Currently this includes X87, SSE,
  AVX, AVX-512, and Intel MPX.
- Add support for injecting hardware exceptions into the guest and use this
  to trigger exceptions in the guest for invalid xsetbv operations instead
  of potentially faulting in the host.
- Queue pending exceptions in the 'struct vcpu' instead of directly updating
  the processor-specific VMCS or VMCB. The pending exception will be delivered
  right before entering the guest.
- Rename the unused ioctl VM_INJECT_EVENT to VM_INJECT_EXCEPTION and restrict
  it to only deliver x86 hardware exceptions. This new ioctl is now used to
  inject a protection fault when the guest accesses an unimplemented MSR.
- Expose a subset of known-safe features from leaf 0 of the structured
  extended features to guests if they are supported on the host including
  RDFSBASE/RDGSBASE, BMI1/2, AVX2, AVX-512, HLE, ERMS, and RTM.  Aside
  from AVX-512, these features are all new instructions available for use
  in ring 3 with no additional hypervisor changes needed.

1 files changed, 10 insertions, 4 deletions

diff --git a/usr.sbin/bhyve/bhyverun.c b/usr.sbin/bhyve/bhyverun.c
index c587aef..b6662ca 100644
--- a/usr.sbin/bhyve/bhyverun.c
+++ b/usr.sbin/bhyve/bhyverun.c
@@ -326,8 +326,11 @@ vmexit_rdmsr(struct vmctx *ctx, struct vm_exit *vme, int *pvcpu)
 	if (error != 0) {
 		fprintf(stderr, "rdmsr to register %#x on vcpu %d\n",
 		    vme->u.msr.code, *pvcpu);
-		if (strictmsr)
-			return (VMEXIT_ABORT);
+		if (strictmsr) {
+			error = vm_inject_exception2(ctx, *pvcpu, IDT_GP, 0);
+			assert(error == 0);
+			return (VMEXIT_RESTART);
+		}
 	}
 
 	eax = val;
@@ -350,8 +353,11 @@ vmexit_wrmsr(struct vmctx *ctx, struct vm_exit *vme, int *pvcpu)
 	if (error != 0) {
 		fprintf(stderr, "wrmsr to register %#x(%#lx) on vcpu %d\n",
 		    vme->u.msr.code, vme->u.msr.wval, *pvcpu);
-		if (strictmsr)
-			return (VMEXIT_ABORT);
+		if (strictmsr) {
+			error = vm_inject_exception2(ctx, *pvcpu, IDT_GP, 0);
+			assert(error == 0);
+			return (VMEXIT_RESTART);
+		}
 	}
 	return (VMEXIT_CONTINUE);
 }