Commit Graph

285 Commits

Author SHA1 Message Date
Neel Natu
5fb3bc71f8 Minor cleanup.
Get rid of unused 'svm_feature' from the softc.

Get rid of the redundant 'vcpu_cnt' checks in svm.c. There is a similar check
in vmm.c against 'vm->active_cpus' before the AMD-specific code is called.

Submitted by:	Anish Gupta (akgupt3@gmail.com)
2014-09-16 04:01:55 +00:00
Neel Natu
79ad53fba3 Use V_IRQ, V_INTR_VECTOR and V_TPR to offload APIC interrupt delivery to the
processor. Briefly, the hypervisor sets V_INTR_VECTOR to the APIC vector
and sets V_IRQ to 1 to indicate a pending interrupt. The hardware then takes
care of injecting this vector when the guest is able to receive it.

Legacy PIC interrupts are still delivered via the event injection mechanism.
This is because the vector injected by the PIC must reflect the state of its
pins at the time the CPU is ready to accept the interrupt.

Accesses to the TPR via %CR8 are handled entirely in hardware. This requires
that the emulated TPR must be synced to V_TPR after a #VMEXIT.

The guest can also modify the TPR via the memory mapped APIC. This requires
that the V_TPR must be synced with the emulated TPR before a VMRUN.

Reviewed by:	Anish Gupta (akgupt3@gmail.com)
2014-09-16 03:31:40 +00:00
Neel Natu
bbadcde418 Set the 'vmexit->inst_length' field properly depending on the type of the
VM-exit and ultimately on whether nRIP is valid. This allows us to update
the %rip after the emulation is finished so any exceptions triggered during
the emulation will point to the right instruction.

Don't attempt to handle INS/OUTS VM-exits unless the DecodeAssist capability
is available. The effective segment field in EXITINFO1 is not valid without
this capability.

Add VM_EXITCODE_SVM to flag SVM VM-exits that cannot be handled. Provide the
VMCB fields exitinfo1 and exitinfo2 as collateral to help with debugging.

Provide a SVM VM-exit handler to dump the exitcode, exitinfo1 and exitinfo2
fields in bhyve(8).

Reviewed by:	Anish Gupta (akgupt3@gmail.com)
Reviewed by:	grehan
2014-09-14 04:39:04 +00:00
Neel Natu
74accc3170 Bug fixes.
- Don't enable the HLT intercept by default. It will be enabled by bhyve(8)
  if required. Prior to this change HLT exiting was always enabled making
  the "-H" option to bhyve(8) meaningless.

- Recognize a VM exit triggered by a non-maskable interrupt. Prior to this
  change the exit would be punted to userspace and the virtual machine would
  terminate.
2014-09-13 23:48:43 +00:00
Neel Natu
fa7caa91cb style(9): insert an empty line if the function has no local variables
Pointed out by:	grehan
2014-09-13 22:45:04 +00:00
Neel Natu
c2a875f970 AMD processors that have the SVM decode assist capability will store the
instruction bytes in the VMCB on a nested page fault. This is useful because
it saves having to walk the guest page tables to fetch the instruction.

vie_init() now takes two additional parameters 'inst_bytes' and 'inst_len'
that map directly to 'vie->inst[]' and 'vie->num_valid'.

The instruction emulation handler skips calling 'vmm_fetch_instruction()'
if 'vie->num_valid' is non-zero.

The use of this capability can be turned off by setting the sysctl/tunable
'hw.vmm.svm.disable_npf_assist' to '1'.

Reviewed by:	Anish Gupta (akgupt3@gmail.com)
Discussed with:	grehan
2014-09-13 22:16:40 +00:00
Neel Natu
442a04ca83 style(9): indent the switch, don't indent the case, indent case body one tab. 2014-09-11 06:17:56 +00:00
Neel Natu
e441104d63 Repurpose the V_IRQ interrupt injection to implement VMX-style interrupt
window exiting. This simply involves setting V_IRQ and enabling the VINTR
intercept. This instructs the CPU to trap back into the hypervisor as soon
as an interrupt can be injected into the guest. The pending interrupt is
then injected via the traditional event injection mechanism.

Rework vcpu interrupt injection so that Linux guests now idle with host cpu
utilization close to 0%.

Reviewed by:	Anish Gupta (earlier version)
Discussed with:	grehan
2014-09-11 02:37:02 +00:00
Neel Natu
238b6cb761 Allow intercepts and irq fields to be cached by the VMCB.
Provide APIs svm_enable_intercept()/svm_disable_intercept() to add/delete
VMCB intercepts. These APIs ensure that the VMCB state cache is invalidated
when intercepts are modified.

Each intercept is identified as a (index,bitmask) tuple. For e.g., the
VINTR intercept is identified as (VMCB_CTRL1_INTCPT,VMCB_INTCPT_VINTR).
The first 20 bytes in control area that are used to enable intercepts
are represented as 'uint32_t intercept[5]' in 'struct vmcb_ctrl'.

Modify svm_setcap() and svm_getcap() to use the new APIs.

Discussed with:	Anish Gupta (akgupt3@gmail.com)
2014-09-10 03:13:40 +00:00
Neel Natu
e5397c9fdd Move the VMCB initialization into svm.c in preparation for changes to the
interrupt injection logic.

Discussed with:	Anish Gupta (akgupt3@gmail.com)
2014-09-10 02:35:19 +00:00
Neel Natu
840b1a2760 Move the event injection function into svm.c and add KTR logging for
every event injection.

This in in preparation for changes to SVM guest interrupt injection.

Discussed with:	Anish Gupta (akgupt3@gmail.com)
2014-09-10 02:20:32 +00:00
Neel Natu
2591ee3e80 Remove a bogus check that flagged an error if the guest %rip was zero.
An AP begins execution with %rip set to 0 after a startup IPI.

Discussed with:	Anish Gupta (akgupt3@gmail.com)
2014-09-10 01:46:22 +00:00
Neel Natu
5e467bd098 Make the KTR tracepoints uniform and ensure that every VM-exit is logged.
Discussed with:	Anish Gupta (akgupt3@gmail.com)
2014-09-10 01:37:32 +00:00
Neel Natu
a2901ce7ad Allow guest read access to MSR_EFER without hypervisor intervention.
Dirty the VMCB_CACHE_CR state cache when MSR_EFER is modified.
2014-09-10 01:10:53 +00:00
Neel Natu
501f03eba2 Remove gratuitous forward declarations.
Remove tabs on empty lines.
2014-09-09 23:39:43 +00:00
Neel Natu
a268481428 Do proper ASID management for guest vcpus.
Prior to this change an ASID was hard allocated to a guest and shared by all
its vcpus. The meant that the number of VMs that could be created was limited
to the number of ASIDs supported by the CPU. It was also inefficient because
it forced a TLB flush on every VMRUN.

With this change the number of guests that can be created is independent of
the number of available ASIDs. Also, the TLB is flushed only when a new ASID
is allocated.

Discussed with:	grehan
Reviewed by:	Anish Gupta (akgupt3@gmail.com)
2014-09-06 19:02:52 +00:00
Neel Natu
3865879753 Merge svm_set_vmcb() and svm_init_vmcb() into a single function that is called
just once when a vcpu is initialized.

Discussed with:	Anish Gupta (akgupt3@gmail.com)
2014-09-05 03:33:16 +00:00
Neel Natu
bf4993ba2a Remove unused header file.
Discussed with:	Anish Gupta (akgupt3@gmail.com)
2014-09-04 06:07:32 +00:00
Neel Natu
fea6bd5cd3 Consolidate the code to restore the host TSS after a #VMEXIT into a single
function restore_host_tss().

Don't bother to restore MSR_KGSBASE after a #VMEXIT since it is not used in
the kernel. It will be restored on return to userspace.

Discussed with:	Anish Gupta (akgupt3@gmail.com)
2014-09-04 06:00:18 +00:00
Neel Natu
246e7a2b64 IFC @r269962
Submitted by:	Anish Gupta (akgupt3@gmail.com)
2014-09-02 04:22:42 +00:00
Neel Natu
48e8c2137a An exception is allowed to be injected even if the vcpu is in an interrupt
shadow, so move the check for pending exception before bailing out due to
an interrupt shadow.

Change return type of 'vmcb_eventinject()' to a void and convert all error
returns into KASSERTs.

Fix VMCB_EXITINTINFO_EC(x) and VMCB_EXITINTINFO_TYPE(x) to do the shift
before masking the result.

Reviewed by:    Anish Gupta (akgupt3@gmail.com)
2014-08-25 00:58:20 +00:00
Neel Natu
477867a0e5 Use the max guest memory address when creating its iommu domain.
Also, assert that the GPA being mapped in the domain is less than its maxaddr.

Reviewed by:	grehan
Pointed out by:	Anish Gupta (akgupt3@gmail.com)
2014-08-14 05:00:45 +00:00
Neel Natu
12a6eb99a1 Support PCI extended config space in bhyve.
Add the ACPI MCFG table to advertise the extended config memory window.

Introduce a new flag MEM_F_IMMUTABLE for memory ranges that cannot be deleted
or moved in the guest's address space. The PCI extended config space is an
example of an immutable memory range.

Add emulation for the "movzw" instruction. This instruction is used by FreeBSD
to read a 16-bit extended config space register.

CR:		https://phabric.freebsd.org/D505
Reviewed by:	jhb, grehan
Requested by:	tychon
2014-08-08 03:49:01 +00:00
John Baldwin
06fc6db948 - Output a summary of optional VT-x features in dmesg similar to CPU
features.  If bootverbose is enabled, a detailed list is provided;
  otherwise, a single-line summary is displayed.
- Add read-only sysctls for optional VT-x capabilities used by bhyve
  under a new hw.vmm.vmx.cap node. Move a few exiting sysctls that
  indicate the presence of optional capabilities under this node.

CR:		https://phabric.freebsd.org/D498
Reviewed by:	grehan, neel
MFC after:	1 week
2014-07-30 00:00:12 +00:00
Neel Natu
f008d1571d If a vcpu has issued a HLT instruction with interrupts disabled then it sleeps
forever in vm_handle_hlt().

This is usually not an issue as long as one of the other vcpus properly resets
or powers off the virtual machine. However, if the bhyve(8) process is killed
with a signal the halted vcpu cannot be woken up because it's sleep cannot be
interrupted.

Fix this by waking up periodically and returning from vm_handle_hlt() if
TDF_ASTPENDING is set.

Reported by:	Leon Dang
Sponsored by:	Nahanni Systems
2014-07-26 02:53:51 +00:00
Neel Natu
1edccd0f30 Don't return -1 from the push emulation handler. Negative return values are
interpreted specially on return from sys_ioctl() and may cause undesirable
side-effects like restarting the system call.
2014-07-26 02:51:46 +00:00
Neel Natu
830be8acb4 Fix a couple of issues in the PUSH emulation:
It is not possible to PUSH a 32-bit operand on the stack in 64-bit mode. The
default operand size for PUSH is 64-bits and the operand size override prefix
changes that to 16-bits.

vm_copy_setup() can return '1' if it encounters a fault when walking the
guest page tables. This is a guest issue and is now handled properly by
resuming the guest to handle the fault.
2014-07-24 23:01:53 +00:00
Neel Natu
d37f2adb38 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 *'.
2014-07-24 01:38:11 +00:00
Neel Natu
d665d229ce Emulate instructions emitted by OpenBSD/i386 version 5.5:
- CMP REG, r/m
- MOV AX/EAX/RAX, moffset
- MOV moffset, AX/EAX/RAX
- PUSH r/m
2014-07-23 04:28:51 +00:00
Neel Natu
019008ebf5 Fix build without INVARIANTS defined by getting rid of unused variable 'exc'.
Reported by:	adrian, stefanf
2014-07-20 16:34:35 +00:00
Neel Natu
091d453222 Handle nested exceptions in bhyve.
A nested exception condition arises when a second exception is triggered while
delivering the first exception. Most nested exceptions can be handled serially
but some are converted into a double fault. If an exception is generated during
delivery of a double fault then the virtual machine shuts down as a result of
a triple fault.

vm_exit_intinfo() is used to record that a VM-exit happened while an event was
being delivered through the IDT. If an exception is triggered while handling
the VM-exit it will be treated like a nested exception.

vm_entry_intinfo() is used by processor-specific code to get the event to be
injected into the guest on the next VM-entry. This function is responsible for
deciding the disposition of nested exceptions.
2014-07-19 20:59:08 +00:00
Neel Natu
3d5444c864 Add emulation for legacy x86 task switching mechanism.
FreeBSD/i386 uses task switching to handle double fault exceptions and this
change enables that to work.

Reported by:	glebius
2014-07-16 21:26:26 +00:00
Neel Natu
f7a9f1784f Add support for operand size and address size override prefixes in bhyve's
instruction emulation [1].

Fix bug in emulation of opcode 0x8A where the destination is a legacy high
byte register and the guest vcpu is in 32-bit mode. Prior to this change
instead of modifying %ah, %bh, %ch or %dh the emulation would end up
modifying %spl, %bpl, %sil or %dil instead.

Add support for moffsets by treating it as a 2, 4 or 8 byte immediate value
during instruction decoding.

Fix bug in verify_gla() where the linear address computed after decoding
the instruction was not being truncated to the effective address size [2].

Tested by:	Leon Dang [1]
Reported by:	Peter Grehan [2]
Sponsored by:	Nahanni Systems
2014-07-15 17:37:17 +00:00
Neel Natu
3ada6e07ac Use the correct offset when converting a logical address (segment:offset)
to a linear address.
2014-07-11 01:23:38 +00:00
Neel Natu
b301b9e28f Accurately identify the vcpu's operating mode as 64-bit, compatibility,
protected or real.
2014-07-08 21:48:57 +00:00
Neel Natu
3527963b26 Invalidate guest TLB mappings as a side-effect of its CR3 being updated.
This is a pre-requisite for task switch emulation since the CR3 is loaded
from the new TSS.
2014-07-08 20:51:03 +00:00
Hans Petter Selasky
af3b2549c4 Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
Glen Barber
37a107a407 Revert r267961, r267973:
These changes prevent sysctl(8) from returning proper output,
such as:

 1) no output from sysctl(8)
 2) erroneously returning ENOMEM with tools like truss(1)
    or uname(1)
 truss: can not get etype: Cannot allocate memory
2014-06-27 22:05:21 +00:00
Hans Petter Selasky
3da1cf1e88 Extend the meaning of the CTLFLAG_TUN flag to automatically check if
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.

Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.

MFC after:	2 weeks
Sponsored by:	Mellanox Technologies
2014-06-27 16:33:43 +00:00
Tycho Nightingale
896d1f7723 Add support for emulating the move instruction: "mov r/m8, imm8".
Reviewed by:	neel
2014-06-26 17:15:41 +00:00
Peter Grehan
cf1d80d88c Expose the amount of resident and wired memory from the guest's vmspace.
This is different than the amount shown for the process e.g. by
/usr/bin/top - that is the mappings faulted in by the mmap'd region
of guest memory.

The values can be fetched with bhyvectl

 # bhyvectl --get-stats --vm=myvm
 ...
 Resident memory                         	413749248
 Wired memory                            	0
 ...

vmm_stat.[ch] -
 Modify the counter code in bhyve to allow direct setting of a counter
as opposed to incrementing, and providing a callback to fetch a
counter's value.

Reviewed by:	neel
2014-06-25 22:13:35 +00:00
Tycho Nightingale
a026dc3fcb Bring an overly enthusiastic KASSERT inline with the Intel SDM.
Reviewed by:	neel
2014-06-16 22:59:18 +00:00
Neel Natu
4e98fc9011 Disable global interrupts early so all the software state maintained by bhyve
is sampled "atomically". Any interrupts after this point will be held pending
by the CPU until the guest starts executing and will immediately trigger a
#VMEXIT.

Reviewed by:	Anish Gupta (akgupt3@gmail.com)
2014-06-11 17:48:07 +00:00
Neel Natu
404874659f Add helper functions to populate VM exit information for rendezvous and
astpending exits. This is to reduce code duplication between VT-x and
SVM implementations.
2014-06-10 16:45:58 +00:00
Neel Natu
0494cb1bcb Turn on interrupt window exiting unconditionally when an ExtINT is being
injected into the guest. This allows the hypervisor to inject another
ExtINT or APIC vector as soon as the guest is able to process interrupts.

This change is not to address any correctness issue but to guarantee that
any pending APIC vector that was preempted by the ExtINT will be injected
as soon as possible. Prior to this change such pending interrupts could be
delayed until the next VM exit.
2014-06-10 01:38:02 +00:00
Peter Grehan
3787148758 Temporary fix for guest idle detection.
Handle ExtINT injection for SVM. The HPET emulation
will inject a legacy interrupt at startup, and if this
isn't handled, will result in the HLT-exit code assuming
there are outstanding ExtINTs and return without sleeping.

svm_inj_interrupts() needs more changes to bring it up
to date with the VT-x version: these are forthcoming.

Reviewed by:	neel
2014-06-09 21:02:48 +00:00
Neel Natu
051f2bd19d Add reserved bit checking when doing %CR8 emulation and inject #GP if required.
Pointed out by:	grehan
Reviewed by:	tychon
2014-06-09 20:51:08 +00:00
Peter Grehan
1cc0e0eedb Allow the TSC MSR to be accessed directly from the guest. 2014-06-07 23:08:06 +00:00
Peter Grehan
dc6610d553 Set the guest PAT MSR in the VMCB to power-on defaults.
Linux guests accept the values in this register, while *BSD
guests reprogram it. Default values of zero correspond to
PAT_UNCACHEABLE, resulting in glacial performance.

Thanks to Willem Jan Withagen for first reporting this and
helping out with the investigation.
2014-06-07 23:05:12 +00:00
Neel Natu
5fcf252f41 Add ioctl(VM_REINIT) to reinitialize the virtual machine state maintained
by vmm.ko. This allows the virtual machine to be restarted without having
to destroy it first.

Reviewed by:	grehan
2014-06-07 21:36:52 +00:00