Commit Graph

245 Commits

Author SHA1 Message Date
Xiaoyao Li a76733a987 KVM: x86: Introduce kvm_check_cpuid()
Use kvm_check_cpuid() to validate if userspace provides legal cpuid
settings and call it before KVM take any action to update CPUID or
update vcpu states based on given CPUID settings.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20200709043426.92712-2-xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-09 06:49:14 -04:00
Xiaoyao Li 36f37648ca KVM: X86: Move kvm_apic_set_version() to kvm_update_cpuid()
There is no dependencies between kvm_apic_set_version() and
kvm_update_cpuid() because kvm_apic_set_version() queries X2APIC CPUID bit,
which is not touched/changed by kvm_update_cpuid().

Obviously, kvm_apic_set_version() belongs to the category of updating
vcpu model.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20200708065054.19713-9-xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-09 06:48:09 -04:00
Xiaoyao Li 0d3b2ba16b KVM: X86: Go on updating other CPUID leaves when leaf 1 is absent
As handling of bits out of leaf 1 added over time, kvm_update_cpuid()
should not return directly if leaf 1 is absent, but should go on
updateing other CPUID leaves.

Keep the update of apic->lapic_timer.timer_mode_mask in a separate
wrapper, to minimize churn for code since it will be moved out of this
function in a future patch.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20200708065054.19713-3-xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-08 16:22:00 -04:00
Xiaoyao Li 1896409282 KVM: X86: Reset vcpu->arch.cpuid_nent to 0 if SET_CPUID* fails
Current implementation keeps userspace input of CPUID configuration and
cpuid->nent even if kvm_update_cpuid() fails. Reset vcpu->arch.cpuid_nent
to 0 for the case of failure as a simple fix.

Besides, update the doc to explicitly state that if IOCTL SET_CPUID*
fail KVM gives no gurantee that previous valid CPUID configuration is
kept.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20200708065054.19713-2-xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-08 16:22:00 -04:00
Like Xu 2e8cd7a3b8 kvm: x86: limit the maximum number of vPMU fixed counters to 3
Some new Intel platforms (such as TGL) already have the
fourth fixed counter TOPDOWN.SLOTS, but it has not been
fully enabled on KVM and the host.

Therefore, we limit edx.split.num_counters_fixed to 3,
so that it does not break the kvm-unit-tests PMU test
case and bad-handled userspace.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Message-Id: <20200624015928.118614-1-like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-08 16:21:59 -04:00
Krish Sadhukhan b899c13277 KVM: x86: Create mask for guest CR4 reserved bits in kvm_update_cpuid()
Instead of creating the mask for guest CR4 reserved bits in kvm_valid_cr4(),
do it in kvm_update_cpuid() so that it can be reused instead of creating it
each time kvm_valid_cr4() is called.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Message-Id: <1594168797-29444-2-git-send-email-krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-08 16:21:58 -04:00
Denis Efremov 7ec28e264f KVM: Use vmemdup_user()
Replace opencoded alloc and copy with vmemdup_user().

Signed-off-by: Denis Efremov <efremov@linux.com>
Message-Id: <20200603101131.2107303-1-efremov@linux.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-04 14:41:05 -04:00
Babu Moger fa44b82eb8 KVM: x86: Move MPK feature detection to common code
Both Intel and AMD support (MPK) Memory Protection Key feature.
Move the feature detection from VMX to the common code. It should
work for both the platforms now.

Signed-off-by: Babu Moger <babu.moger@amd.com>
Message-Id: <158932795627.44260.15144185478040178638.stgit@naples-babu.amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-04 12:35:06 -04:00
Xiaoyao Li 65b1891499 KVM: x86: Assign correct value to array.maxnent
Delay the assignment of array.maxnent to use correct value for the case
cpuid->nent > KVM_MAX_CPUID_ENTRIES.

Fixes: e53c95e8d4 ("KVM: x86: Encapsulate CPUID entries and metadata in struct")
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20200604041636.1187-1-xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-04 12:21:10 -04:00
Like Xu 27461da310 KVM: x86/pmu: Support full width counting
Intel CPUs have a new alternative MSR range (starting from MSR_IA32_PMC0)
for GP counters that allows writing the full counter width. Enable this
range from a new capability bit (IA32_PERF_CAPABILITIES.FW_WRITE[bit 13]).

The guest would query CPUID to get the counter width, and sign extends
the counter values as needed. The traditional MSRs always limit to 32bit,
even though the counter internally is larger (48 or 57 bits).

When the new capability is set, use the alternative range which do not
have these restrictions. This lowers the overhead of perf stat slightly
because it has to do less interrupts to accumulate the counter value.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Message-Id: <20200529074347.124619-3-like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-01 04:26:09 -04:00
Vitaly Kuznetsov 72de5fa4c1 KVM: x86: announce KVM_FEATURE_ASYNC_PF_INT
Introduce new capability to indicate that KVM supports interrupt based
delivery of 'page ready' APF events. This includes support for both
MSR_KVM_ASYNC_PF_INT and MSR_KVM_ASYNC_PF_ACK.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200525144125.143875-8-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-06-01 04:26:08 -04:00
Xiaoyao Li a71936ab46 kvm: x86: Cleanup vcpu->arch.guest_xstate_size
vcpu->arch.guest_xstate_size lost its only user since commit df1daba7d1
("KVM: x86: support XSAVES usage in the host"), so clean it up.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20200429154312.1411-1-xiaoyao.li@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-15 12:26:10 -04:00
Sean Christopherson e93fd3b3e8 KVM: x86/mmu: Capture TDP level when updating CPUID
Snapshot the TDP level now that it's invariant (SVM) or dependent only
on host capabilities and guest CPUID (VMX).  This avoids having to call
kvm_x86_ops.get_tdp_level() when initializing a TDP MMU and/or
calculating the page role, and thus avoids the associated retpoline.

Drop the WARN in vmx_get_tdp_level() as updating CPUID while L2 is
active is legal, if dodgy.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200502043234.12481-11-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:15:14 -04:00
Eric Northup 43d05de2be KVM: pass through CPUID(0x80000006)
Return the host's L2 cache and TLB information for CPUID.0x80000006
instead of zeroing out the entry as part of KVM_GET_SUPPORTED_CPUID.
This allows a userspace VMM to feed KVM_GET_SUPPORTED_CPUID's output
directly into KVM_SET_CPUID2 (without breaking the guest).

Signed-off-by: Eric Northup (Google) <digitaleric@gmail.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Jon Cargille <jcargill@google.com>
Message-Id: <20200415012320.236065-1-jcargill@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-04-15 12:08:41 -04:00
Sean Christopherson 855c7e9b9c KVM: x86: Fix BUILD_BUG() in __cpuid_entry_get_reg() w/ CONFIG_UBSAN=y
Take the target reg in __cpuid_entry_get_reg() instead of a pointer to a
struct cpuid_reg.  When building with -fsanitize=alignment (enabled by
CONFIG_UBSAN=y), some versions of gcc get tripped up on the pointer and
trigger the BUILD_BUG().

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Fixes: d8577a4c23 ("KVM: x86: Do host CPUID at load time to mask KVM cpu caps")
Fixes: 4c61534aaa ("KVM: x86: Introduce cpuid_entry_{get,has}() accessors")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200325191259.23559-1-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-31 10:51:45 -04:00
Sean Christopherson afaf0b2f9b KVM: x86: Copy kvm_x86_ops by value to eliminate layer of indirection
Replace the kvm_x86_ops pointer in common x86 with an instance of the
struct to save one pointer dereference when invoking functions.  Copy the
struct by value to set the ops during kvm_init().

Arbitrarily use kvm_x86_ops.hardware_enable to track whether or not the
ops have been initialized, i.e. a vendor KVM module has been loaded.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200321202603.19355-7-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-31 10:48:08 -04:00
Zhenyu Wang e3747407c4 KVM: x86: Expose fast short REP MOV for supported cpuid
For CPU supporting fast short REP MOV (XF86_FEATURE_FSRM) e.g Icelake,
Tigerlake, expose it in KVM supported cpuid as well.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Message-Id: <20200323092236.3703-1-zhenyuw@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-23 15:44:24 -04:00
Sean Christopherson 2b110b6164 KVM: x86: Add blurb to CPUID tracepoint when using max basic leaf values
Tack on "used max basic" at the end of the CPUID tracepoint when the
output values correspond to the max basic leaf, i.e. when emulating
Intel's out-of-range CPUID behavior.  Observing "cpuid entry not found"
in the tracepoint with non-zero output values is confusing for users
that aren't familiar with the out-of-range semantics, and qualifying the
"not found" case hopefully makes it clear that "found" means "found the
exact entry".

Suggested-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-18 13:44:43 +01:00
Sean Christopherson e7adda2810 KVM: x86: Add requested index to the CPUID tracepoint
Output the requested index when tracing CPUID emulation; it's basically
mandatory for leafs where the index is meaningful, and is helpful for
verifying KVM correctness even when the index isn't meaningful, e.g. the
trace for a Linux guest's hypervisor_cpuid_base() probing appears to
be broken (returns all zeroes) at first glance, but is correct because
the index is non-zero, i.e. the output values correspond to a random
index in the maximum basic leaf.

Suggested-by: Xiaoyao Li <xiaoyao.li@intel.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-18 13:44:18 +01:00
Zhenyu Wang 9401f2e5b0 KVM: x86: Expose AVX512 VP2INTERSECT in cpuid for TGL
On Tigerlake new AVX512 VP2INTERSECT feature is available.
This allows to expose it via KVM_GET_SUPPORTED_CPUID.

Cc: "Zhong, Yang" <yang.zhong@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-18 12:25:45 +01:00
Sean Christopherson f91af5176c KVM: x86: Refactor kvm_cpuid() param that controls out-of-range logic
Invert and rename the kvm_cpuid() param that controls out-of-range logic
to better reflect the semantics of the affected callers, i.e. callers
that bypass the out-of-range logic do so because they are looking up an
exact guest CPUID entry, e.g. to query the maxphyaddr.

Similarly, rename kvm_cpuid()'s internal "found" to "exact" to clarify
that it tracks whether or not the exact requested leaf was found, as
opposed to any usable leaf being found.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:50 +01:00
Sean Christopherson 09c7431ed3 KVM: x86: Refactor out-of-range logic to contain the madness
Move all of the out-of-range logic into a single helper,
get_out_of_range_cpuid_entry(), to avoid an extra lookup of CPUID.0.0
and to provide a single location for documenting the out-of-range
behavior.

No functional change intended.

Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:49 +01:00
Sean Christopherson 8d8923115f KVM: x86: Fix CPUID range checks for Hypervisor and Centaur classes
Rework the masking in the out-of-range CPUID logic to handle the
Hypervisor sub-classes, as well as the Centaur class if the guest
virtual CPU vendor is Centaur.

Masking against 0x80000000 only handles basic and extended leafs, which
results in Hypervisor range checks being performed against the basic
CPUID class, and Centuar range checks being performed against the
Extended class.  E.g. if CPUID.0x40000000.EAX returns 0x4000000A and
there is no entry for CPUID.0x40000006, then function 0x40000006 would
be incorrectly reported as out of bounds.

While there is no official definition of what constitutes a class, the
convention established for Hypervisor classes effectively uses bits 31:8
as the mask by virtue of checking for different bases in increments of
0x100, e.g. KVM advertises its CPUID functions starting at 0x40000100
when HyperV features are advertised at the default base of 0x40000000.

The bad range check doesn't cause functional problems for any known VMM
because out-of-range semantics only come into play if the exact entry
isn't found, and VMMs either support a very limited Hypervisor range,
e.g. the official KVM range is 0x40000000-0x40000001 (effectively no
room for undefined leafs) or explicitly defines gaps to be zero, e.g.
Qemu explicitly creates zeroed entries up to the Centaur and Hypervisor
limits (the latter comes into play when providing HyperV features).

The bad behavior can be visually confirmed by dumping CPUID output in
the guest when running Qemu with a stable TSC, as Qemu extends the limit
of range 0x40000000 to 0x40000010 to advertise VMware's cpuid_freq,
without defining zeroed entries for 0x40000002 - 0x4000000f.

Note, documentation of Centaur/VIA CPUs is hard to come by.  Designating
0xc0000000 - 0xcfffffff as the Centaur class is a best guess as to the
behavior of a real Centaur/VIA CPU.

Fixes: 43561123ab ("kvm: x86: Improve emulation of CPUID leaves 0BH and 1FH")
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:49 +01:00
Sean Christopherson 23493d0a17 KVM x86: Extend AMD specific guest behavior to Hygon virtual CPUs
Extend guest_cpuid_is_amd() to cover Hygon virtual CPUs and rename it
accordingly.  Hygon CPUs use an AMD-based core and so have the same
basic behavior as AMD CPUs.

Fixes: b8f4abb652 ("x86/kvm: Add Hygon Dhyana support to KVM")
Cc: Pu Wen <puwen@hygon.cn>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:48 +01:00
Jan Kiszka b7fb8488c8 KVM: x86: Trace the original requested CPUID function in kvm_cpuid()
Trace the requested CPUID function instead of the effective function,
e.g. if the requested function is out-of-range and KVM is emulating an
Intel CPU, as the intent of the tracepoint is to show if the output came
from the actual leaf as opposed to the max basic leaf via redirection.

Similarly, leave "found" as is, i.e. report that an entry was found if
and only if the requested entry was found.

Fixes: 43561123ab ("kvm: x86: Improve emulation of CPUID leaves 0BH and 1FH")
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
[Sean: Drop "found" semantic change, reword changelong accordingly ]
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:46 +01:00
Paolo Bonzini 408e9a318f KVM: CPUID: add support for supervisor states
Current CPUID 0xd enumeration code does not support supervisor
states, because KVM only supports setting IA32_XSS to zero.
Change it instead to use a new variable supported_xss, to be
set from the hardware_setup callback which is in charge of CPU
capabilities.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:45 +01:00
Sean Christopherson 257038745c KVM: x86: Move nSVM CPUID 0x8000000A handling into common x86 code
Handle CPUID 0x8000000A in the main switch in __do_cpuid_func() and drop
->set_supported_cpuid() now that both VMX and SVM implementations are
empty.  Like leaf 0x14 (Intel PT) and leaf 0x8000001F (SEV), leaf
0x8000000A is is (obviously) vendor specific but can be queried in
common code while respecting SVM's wishes by querying kvm_cpu_cap_has().

Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:45 +01:00
Sean Christopherson 91661989d1 KVM: x86: Move VMX's host_efer to common x86 code
Move host_efer to common x86 code and use it for CPUID's is_efer_nx() to
avoid constantly re-reading the MSR.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:42 +01:00
Sean Christopherson 7c7f954810 KVM: x86: Do kvm_cpuid_array capacity checks in terminal functions
Perform the capacity checks on the userspace provided kvm_cpuid_array
in the lower __do_cpuid_func() and __do_cpuid_func_emulated().
Pre-checking the array in do_cpuid_func() no longer adds value now that
__do_cpuid_func() has been trimmed down to size, i.e. doesn't invoke a
big pile of retpolined functions before doing anything useful.

Note, __do_cpuid_func() already checks the array capacity via
do_host_cpuid(), "moving" the check to __do_cpuid_func() simply means
removing a WARN_ON().

Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:35 +01:00
Sean Christopherson dd69cc2542 KVM: x86: Use kvm_cpu_caps to detect Intel PT support
Check for Intel PT using kvm_cpu_cap_has() to pave the way toward
eliminating ->pt_supported().

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:34 +01:00
Sean Christopherson 93c380e7b5 KVM: x86: Set emulated/transmuted feature bits via kvm_cpu_caps
Set emulated and transmuted (set based on other features) feature bits
via kvm_cpu_caps now that the CPUID output for KVM_GET_SUPPORTED_CPUID
is direcly overidden with kvm_cpu_caps.

Note, VMX emulation of UMIP already sets kvm_cpu_caps.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:33 +01:00
Sean Christopherson bd79199990 KVM: x86: Override host CPUID results with kvm_cpu_caps
Override CPUID entries with kvm_cpu_caps during KVM_GET_SUPPORTED_CPUID
instead of masking the host CPUID result, which is redundant now that
the host CPUID is incorporated into kvm_cpu_caps at runtime.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:32 +01:00
Sean Christopherson d8577a4c23 KVM: x86: Do host CPUID at load time to mask KVM cpu caps
Mask kvm_cpu_caps based on host CPUID in preparation for overriding the
CPUID results during KVM_GET_SUPPORTED_CPUID instead of doing the
masking at runtime.

Note, masking may or may not be necessary, e.g. the kernel rarely, if
ever, sets real CPUID bits that are not supported by hardware.  But, the
code is cheap and only runs once at load, so an abundance of caution is
warranted.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:31 +01:00
Sean Christopherson 7ff6c03503 KVM: x86: Remove stateful CPUID handling
Remove the code for handling stateful CPUID 0x2 and mark the associated
flags as deprecated.  WARN if host CPUID 0x2.0.AL > 1, i.e. if by some
miracle a host with stateful CPUID 0x2 is encountered.

No known CPU exists that supports hardware accelerated virtualization
_and_ a stateful CPUID 0x2.  Barring an extremely contrived nested
virtualization scenario, stateful CPUID support is dead code.

Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:31 +01:00
Sean Christopherson c571a144ef KVM: x86: Squash CPUID 0x2.0 insanity for modern CPUs
Rework CPUID 0x2.0 to be a normal CPUID leaf if it returns "01" in AL,
i.e. EAX & 0xff, as a step towards removing KVM's stateful CPUID code
altogether.

Long ago, Intel documented CPUID 0x2.0 as being a stateful leaf, e.g. a
version of the SDM circa 1995 states:

  The least-significant byte in register EAX (register AL) indicates the
  number of times the CPUID instruction must be executed with an input
  value of 2 to get a complete description of the processors's caches
  and TLBs.  The Pentium Pro family of processors will return a 1.

A 2000 version of the SDM only updated the paragraph to reference
Intel's new processory family:

  The first member of the family of Pentium 4 processors will return a 1.

Fast forward to the present, and Intel's SDM now states:

  The least-significant byte in register EAX (register AL) will always
  return 01H.  Software should ignore this value and not interpret it as
  an information descriptor.

AMD's APM simply states that CPUID 0x2 is reserved.

Given that CPUID itself was introduced in the Pentium, odds are good
that the only Intel CPU family that *maybe* implemented a stateful CPUID
was the P5.  Which obviously did not support VMX, or KVM.

In other words, KVM's emulation of a stateful CPUID 0x2.0 has likely
been dead code from the day it was introduced.  This is backed up by
commit 0fdf8e59fa ("KVM: Fix cpuid iteration on multiple leaves per
eac"), which shows that the stateful iteration code was completely
broken when it was introduced by commit 0771671749 ("KVM: Enhance
guest cpuid management"), i.e. not actually tested.

Annotate all stateful code paths as "unlikely", but defer its removal to
a future patch to simplify reinstating the code if by some miracle there
is someone running KVM on a CPU with a stateful CPUID 0x2.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:30 +01:00
Sean Christopherson bcf600ca8d KVM: x86: Remove the unnecessary loop on CPUID 0x7 sub-leafs
Explicitly handle CPUID 0x7 sub-leaf 1.  The kernel is currently aware
of exactly one feature in CPUID 0x7.1,  which means there is room for
another 127 features before CPUID 0x7.2 will see the light of day, i.e.
the looping is likely to be dead code for years to come.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:29 +01:00
Sean Christopherson 09f628a0b4 KVM: x86: Fold CPUID 0x7 masking back into __do_cpuid_func()
Move the CPUID 0x7 masking back into __do_cpuid_func() now that the
size of the code has been trimmed down significantly.

Tweak the WARN case, which is impossible to hit unless the CPU is
completely broken, to break the loop before creating the bogus entry.

Opportunustically reorder the cpuid_entry_set() calls and shorten the
comment about emulation to further reduce the footprint of CPUID 0x7.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:28 +01:00
Sean Christopherson b3d895d5c4 KVM: x86: Move XSAVES CPUID adjust to VMX's KVM cpu cap update
Move the clearing of the XSAVES CPUID bit into VMX, which has a separate
VMCS control to enable XSAVES in non-root, to eliminate the last ugly
renmant of the undesirable "unsigned f_* = *_supported ? F(*) : 0"
pattern in the common CPUID handling code.

Drop ->xsaves_supported(), CPUID adjustment was the only user.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:25 +01:00
Sean Christopherson 9b58b9857f KVM: SVM: Convert feature updates from CPUID to KVM cpu caps
Use the recently introduced KVM CPU caps to propagate SVM-only (kernel)
settings to supported CPUID flags.

Note, there are a few subtleties:

  - Setting a flag based on a *different* feature is effectively
    emulation, and must be done at runtime via ->set_supported_cpuid().

  - CPUID 0x8000000A.EDX is a feature leaf that was previously not
    adjusted by kvm_cpu_cap_mask() because all features are hidden by
    default.

Opportunistically add a technically unnecessary break and fix an
indentation issue in svm_set_supported_cpuid().

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:24 +01:00
Sean Christopherson 66a6950f99 KVM: x86: Introduce kvm_cpu_caps to replace runtime CPUID masking
Calculate the CPUID masks for KVM_GET_SUPPORTED_CPUID at load time using
what is effectively a KVM-adjusted copy of boot_cpu_data, or more
precisely, the x86_capability array in boot_cpu_data.

In terms of KVM support, the vast majority of CPUID feature bits are
constant, and *all* feature support is known at KVM load time.  Rather
than apply boot_cpu_data, which is effectively read-only after init,
at runtime, copy it into a KVM-specific array and use *that* to mask
CPUID registers.

In additional to consolidating the masking, kvm_cpu_caps can be adjusted
by SVM/VMX at load time and thus eliminate all feature bit manipulation
in ->set_supported_cpuid().

Opportunistically clean up a few warts:

  - Replace bare "unsigned" with "unsigned int" when a feature flag is
    captured in a local variable, e.g. f_nx.

  - Sort the CPUID masks by function, index and register (alphabetically
    for registers, i.e. EBX comes before ECX/EDX).

  - Remove the superfluous /* cpuid 7.0.ecx */ comments.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Call kvm_set_cpu_caps from kvm_x86_ops->hardware_setup due to fixed
 GBPAGES patch. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:23 +01:00
Sean Christopherson 9e6d01c2d9 KVM: x86: Refactor handling of XSAVES CPUID adjustment
Invert the handling of XSAVES, i.e. set it based on boot_cpu_has() by
default, in preparation for adding KVM cpu caps, which will generate the
mask at load time before ->xsaves_supported() is ready.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:22 +01:00
Paolo Bonzini fb7d4377d5 KVM: x86: handle GBPAGE CPUID adjustment for EPT with generic code
The clearing of the GBPAGE CPUID bit for VMX is wrong; support for 1GB
pages in EPT has no relationship to whether 1GB pages should be marked as
supported in CPUID.  This has no ill effect because we're only clearing
the bit, but we're not marking 1GB pages as available when EPT is disabled
(even though they are actually supported thanks to shadowing).  Instead,
forcibly enable 1GB pages in the shadow paging case.

This also eliminates an instance of the undesirable "unsigned f_* =
*_supported ? F(*) : 0" pattern in the common CPUID handling code,
and paves the way toward eliminating ->get_lpage_level().

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:21 +01:00
Sean Christopherson dbd068040c KVM: x86: Handle Intel PT CPUID adjustment in VMX code
Move the Processor Trace CPUID adjustment into VMX code to eliminate
an instance of the undesirable "unsigned f_* = *_supported ? F(*) : 0"
pattern in the common CPUID handling code, and to pave the way toward
eventually removing ->pt_supported().

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:20 +01:00
Sean Christopherson 733deafc00 KVM: x86: Handle RDTSCP CPUID adjustment in VMX code
Move the clearing of the RDTSCP CPUID bit into VMX, which has a separate
VMCS control to enable RDTSCP in non-root, to eliminate an instance of
the undesirable "unsigned f_* = *_supported ? F(*) : 0" pattern in the
common CPUID handling code.  Drop ->rdtscp_supported() since CPUID
adjustment was the last remaining user.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:20 +01:00
Sean Christopherson d64d83d1e0 KVM: x86: Handle PKU CPUID adjustment in VMX code
Move the setting of the PKU CPUID bit into VMX to eliminate an instance
of the undesirable "unsigned f_* = *_supported ? F(*) : 0" pattern in
the common CPUID handling code.  Drop ->pku_supported(), CPUID
adjustment was the only user.

Note, some AMD CPUs now support PKU, but SVM doesn't yet support
exposing it to a guest.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:19 +01:00
Sean Christopherson e574768f84 KVM: x86: Handle UMIP emulation CPUID adjustment in VMX code
Move the CPUID adjustment for UMIP emulation into VMX code to eliminate
an instance of the undesirable "unsigned f_* = *_supported ? F(*) : 0"
pattern in the common CPUID handling code.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:18 +01:00
Sean Christopherson 5ffec6f910 KVM: x86: Handle INVPCID CPUID adjustment in VMX code
Move the INVPCID CPUID adjustments into VMX to eliminate an instance of
the undesirable "unsigned f_* = *_supported ? F(*) : 0" pattern in the
common CPUID handling code.  Drop ->invpcid_supported(), CPUID
adjustment was the only user.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:17 +01:00
Sean Christopherson 6c7ea4b56b KVM: x86: Handle MPX CPUID adjustment in VMX code
Move the MPX CPUID adjustments into VMX to eliminate an instance of the
undesirable "unsigned f_* = *_supported ? F(*) : 0" pattern in the
common CPUID handling code.

Note, to maintain existing behavior, VMX must manually check for kernel
support for MPX by querying boot_cpu_has(X86_FEATURE_MPX).  Previously,
do_cpuid_7_mask() masked MPX based on boot_cpu_data by invoking
cpuid_mask() on the associated cpufeatures word, but cpuid_mask() runs
prior to executing vmx_set_supported_cpuid().

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:17 +01:00
Sean Christopherson e745e37d49 KVM: x86: Refactor cpuid_mask() to auto-retrieve the register
Use the recently introduced cpuid_entry_get_reg() to automatically get
the appropriate register when masking a CPUID entry.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:16 +01:00
Sean Christopherson b32666b13a KVM: x86: Introduce cpuid_entry_{change,set,clear}() mutators
Introduce mutators to modify feature bits in CPUID entries and use the
new mutators where applicable.  Using the mutators eliminates the need
to manually specify the register to modify query at no extra cost and
will allow adding runtime consistency checks on the function/index in a
future patch.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:58:15 +01:00