Commit Graph

33 Commits

Author SHA1 Message Date
Neel Natu
150369ab7c Make the code to check if VMX is enabled more readable by using macros
instead of magic numbers.

Discussed with:	Chris Torek
2013-04-11 04:29:45 +00:00
Neel Natu
b5aaf7b22b Add some more stats to keep track of all the reasons that a vcpu is exiting. 2013-03-30 17:46:03 +00:00
Neel Natu
61592433eb Allow vmm stats to be specific to the underlying hardware assist technology.
This can be done by using the new macros VMM_STAT_INTEL() and VMM_STAT_AMD().
Statistic counters that are common across the two are defined using VMM_STAT().

Suggested by:	Anish Gupta
Discussed with:	grehan
Obtained from:	NetApp
2013-03-16 22:40:20 +00:00
Peter Grehan
1fb0ea3f1a Always allow access to the sysenter cs/esp/eip MSRs since they
are automatically saved and restored in the VMCS.

Reviewed by:	neel
Obtained from:	NetApp
2013-01-25 21:38:31 +00:00
Peter Grehan
3b2b001107 Add support for the 0x81 AND instruction, now generated
by clang in the local APIC code.

0x81 is a read-modify-write instruction - the EPT check
that only allowed read or write and not both has been
relaxed to allow read and write.

Reviewed by:	neel
Obtained from:	NetApp
2012-11-29 06:26:42 +00:00
Neel Natu
48a29f4e07 Cleanup the user-space paging exit handler now that the unified instruction
emulation is in place.

Obtained from:	NetApp
2012-11-28 13:34:44 +00:00
Neel Natu
b42206f300 Change emulate_rdmsr() and emulate_wrmsr() to return 0 on sucess and errno on
failure. The conversion from the return value to HANDLED or UNHANDLED can be
done locally in vmx_exit_process().

Obtained from: NetApp
2012-11-28 13:10:18 +00:00
Neel Natu
ba9b7bf73a Revamp the x86 instruction emulation in bhyve.
On a nested page table fault the hypervisor will:
- fetch the instruction using the guest %rip and %cr3
- decode the instruction in 'struct vie'
- emulate the instruction in host kernel context for local apic accesses
- any other type of mmio access is punted up to user-space (e.g. ioapic)

The decoded instruction is passed as collateral to the user-space process
that is handling the PAGING exit.

The emulation code is fleshed out to include more addressing modes (e.g. SIB)
and more types of operands (e.g. imm8). The source code is unified into a
single file (vmm_instruction_emul.c) that is compiled into vmm.ko as well
as /usr/sbin/bhyve.

Reviewed by:	grehan
Obtained from:	NetApp
2012-11-28 00:02:17 +00:00
Neel Natu
288aeb8561 Get rid of redundant comparision which is guaranteed to be "true" for unsigned
integers.

Obtained from:	NetApp
2012-11-22 00:08:20 +00:00
Peter Grehan
0a5e9bfb72 Fix issue found with clang build. Avoid code insertion by the compiler
between inline asm statements that would in turn modify the flags
value set by the first asm, and used by the second.

Solve by making the common error block a string that can be pulled
into the first inline asm, and using symbolic labels for asm variables.

bhyve can now build/run fine when compiled with clang.

Reviewed by:	neel
Obtained from:	NetApp
2012-11-06 02:43:41 +00:00
Neel Natu
514393f565 Convert VMCS_ENTRY_INTR_INFO field into a vmcs identifier before passing it
to vmcs_getreg(). Without this conversion vmcs_getreg() will return EINVAL.

In particular this prevented injection of the breakpoint exception into the
guest via the "-B" option to /usr/sbin/bhyve which is hugely useful when
debugging guest hangs.

This was broken in r241921.

Pointy hat: me
Obtained from:	NetApp
2012-10-29 23:58:15 +00:00
Neel Natu
b01c203325 Corral all the host state associated with the virtual machine into its own file.
This state is independent of the type of hardware assist used so there is
really no need for it to be in Intel-specific code.

Obtained from:	NetApp
2012-10-29 01:51:24 +00:00
Neel Natu
bd8572e0be Unconditionally enable fpu emulation by setting CR0.TS in the host after the
guest does a vm exit.

This allows us to trap any fpu access in the host context while the fpu still
has "dirty" state belonging to the guest.

Reported by: "s vas" on freebsd-virtualization@
Obtained from:	NetApp
2012-10-26 03:12:40 +00:00
Neel Natu
f76fc5d414 If the guest vcpu wants to idle then use that opportunity to relinquish the
host cpu to the scheduler until the guest is ready to run again.

This implies that the host cpu utilization will now closely mirror the actual
load imposed by the guest vcpu.

Also, the vcpu mutex now needs to be of type MTX_SPIN since we need to acquire
it inside a critical section.

Obtained from:	NetApp
2012-10-25 04:29:21 +00:00
Neel Natu
f352ff0ca8 Maintain state regarding NMI delivery to guest vcpu in VT-x independent manner.
Also add a stats counter to count the number of NMIs delivered per vcpu.

Obtained from:	NetApp
2012-10-24 02:54:21 +00:00
Neel Natu
eeefa4e4be Test for AST pending with interrupts disabled right before entering the guest.
If an IPI was delivered to this cpu before interrupts were disabled
then return right away via vmx_setjmp() with a return value of VMX_RETURN_AST.

Obtained from:	NetApp
2012-10-23 02:20:42 +00:00
Peter Grehan
13ec93719a Add the guest physical address and r/w/x bits to
the paging exit in preparation for a rework of
bhyve MMIO handling.

Reviewed by:	neel
Obtained from:	NetApp
2012-10-12 23:12:19 +00:00
Neel Natu
75dd336603 Provide per-vcpu locks instead of relying on a single big lock.
This also gets rid of all the witness.watch warnings related to calling
malloc(M_WAITOK) while holding a mutex.

Reviewed by:	grehan
2012-10-12 18:32:44 +00:00
Neel Natu
7ce04d0ad9 Allocate memory pages for the guest from the host's free page queue.
It is no longer necessary to hard-partition the memory between the host
and guests at boot time.
2012-10-08 23:41:26 +00:00
Neel Natu
bda273f21e Get rid of assumptions in the hypervisor that the host physical memory
associated with guest physical memory is contiguous.

Rewrite vm_gpa2hpa() to get the GPA to HPA mapping by querying the nested
page tables.
2012-10-03 00:46:30 +00:00
Neel Natu
70593114cd Intel VT-x provides the length of the instruction at the time of the nested
page table fault. Use this when fetching the instruction bytes from the guest
memory.

Also modify the lapic_mmio() API so that a decoded instruction is fed into it
instead of having it fetch the instruction bytes from the guest. This is
useful for hardware assists like SVM that provide the faulting instruction
as part of the vmexit.
2012-09-27 00:27:58 +00:00
Neel Natu
a2da7af6bc Add support for trapping MMIO writes to local apic registers and emulating them.
The default behavior is still to present the local apic to the guest in the
x2apic mode.
2012-09-25 22:31:35 +00:00
Neel Natu
edf89256dd Add an explicit exit code 'SPINUP_AP' to tell the controlling process that an
AP needs to be activated by spinning up an execution context for it.

The local apic emulation is now completely done in the hypervisor and it will
detect writes to the ICR_LO register that try to bring up the AP. In response
to such writes it will return to userspace with an exit code of SPINUP_AP.

Reviewed by: grehan
2012-09-25 02:33:25 +00:00
Neel Natu
98ed632c63 Stash the 'vm_exit' information in each 'struct vcpu'.
There is no functional change at this time but this paves the way for vm exit
handler functions to easily modify the exit reason going forward.
2012-09-24 19:32:24 +00:00
Neel Natu
39c21c2db2 Force certain bits in %cr4 to be hard-wired to '1' or '0' from a guest's
perspective. If we don't do this some guest OSes (e.g. Linux) will reset
the CR4_VMXE bit in %cr4 with disastrous consequences.

Reported by: grehan
2012-08-04 02:06:55 +00:00
Neel Natu
4bff7fad95 Verify that VMX operation has been enabled by BIOS before executing the
VMXON instruction.

Reported by "s vas" on freebsd-virtualization@
2012-07-25 00:21:16 +00:00
Peter Grehan
cd942e0f25 MSI-x interrupt support for PCI pass-thru devices.
Includes instruction emulation for memory r/w access. This
opens the door for io-apic, local apic, hpet timer, and
legacy device emulation.

Submitted by:	ryan dot berryhill at sandvine dot com
Reviewed by:	grehan
Obtained from:	Sandvine
2012-04-28 16:28:00 +00:00
Peter Grehan
608f97c359 Add support for running as a nested hypervisor under VMWare Fusion, on
systems with VT-x/EPT (e.g. Sandybridge Macbooks). This will most
likely work on VMWare Workstation8/Player4 as well. See the VMWare app
note at:

  http://communities.vmware.com/docs/DOC-8970

Fusion doesn't propagate the PAT MSR auto save-restore entry/exit
control bits. Deal with this by noting that fact and setting up the
PAT MSR to essentially be a no-op - it is init'd to power-on default,
and a software shadow copy maintained.

Since it is treated as a no-op, o/s settings are essentially ignored.
This may not give correct results, but since the hypervisor is running
nested, a number of bets are already off.

On a quad-core/HT-enabled 'MacBook8,2', nested VMs with 1/2/4 vCPUs were
fired up. The more nested vCPUs the worse the performance, unless the VMs
were started up in multiplexed mode where things worked perfectly up to
the limit of 8 vCPUs.

Reviewed by:	neel
2011-12-24 19:39:02 +00:00
John Baldwin
8b28761278 Some tweaks to the CPUID support:
- Don't always pass the cpuid request to the current CPU as some nodes
  we will emulate purely in software.
- Pass in the APIC ID of the virtual CPU so we can return the proper APIC
  ID.
- Always report a completely flat topology with no SMT or multicore.
- Report the CPUID2_HV feature and implement support for the 0x40000000
  CPUID level.
- Use existing constants from <machine/specialreg.h> when possible and
  use cpu_feature2 when checking for VMX support.
2011-06-02 14:04:07 +00:00
John Baldwin
b3996dd47c Add a 'show vmcs' DDB command to dump state about the current CPU's
current VMCS.
2011-06-02 13:49:19 +00:00
Neel Natu
ad54f37429 Fix a long standing bug in VMXCTX_GUEST_RESTORE().
There was an assumption by the "callers" of this macro that on "return" the
%rsp will be pointing to the 'vmxctx'. The macro was not doing this and thus
when trying to restore host state on an error from "vmlaunch" or "vmresume"
we were treating the memory locations on the host stack as 'struct vmxctx'.
This led to all sorts of weird bugs like double faults or invalid instruction
faults.

This bug is exposed by the -O2 option used to compile the kernel module. With
the -O2 flag the compiler will optimize the following piece of code:

	int loopstart = 1;
	...
	if (loopstart) {
		loopstart = 0;
		vmx_launch();
	} else
		vmx_resume();

into this:

	vmx_launch();

Since vmx_launch() and vmx_resume() are declared to be __dead2 functions the
compiler is free to do this. The compiler has no way to know that the
functions return indirectly through vmx_setjmp(). This optimization in turn
leads us to trigger the bug in VMXCTX_GUEST_RESTORE().

With this change we can boot a 8.1 guest on a 9.0 host.

Reported by: jhb@
2011-05-20 03:23:09 +00:00
Neel Natu
3caf3beb5c Avoid unnecessary sign extension when promoted to a 64-bit integer.
This was benign because the interruption info field is a 32-bit quantity and
the hardware guarantees that the upper 32-bits are all zeros. But it did make
reading the objdump output very confusing.
2011-05-20 02:08:05 +00:00
Peter Grehan
366f60834f Import of bhyve hypervisor and utilities, part 1.
vmm.ko - kernel module for VT-x, VT-d and hypervisor control
  bhyve  - user-space sequencer and i/o emulation
  vmmctl - dump of hypervisor register state
  libvmm - front-end to vmm.ko chardev interface

bhyve was designed and implemented by Neel Natu.

Thanks to the following folk from NetApp who helped to make this available:
	Joe CaraDonna
	Peter Snyder
	Jeff Heller
	Sandeep Mann
	Steve Miller
	Brian Pawlowski
2011-05-13 04:54:01 +00:00