Currently, there are two definitions related to huge page, but a little bit
far from each other and seems loosely connected:

 * KVM_NR_PAGE_SIZES defines the number of different size a page could map
 * PT_MAX_HUGEPAGE_LEVEL means the maximum level of huge page

The number of different size a page could map equals the maximum level
of huge page, which is implied by current definition.

While current implementation may not be kind to readers and further
developers:

 * KVM_NR_PAGE_SIZES looks like a stand alone definition at first sight
 * in case we need to support more level, two places need to change

This patch tries to make these two definition more close, so that reader
and developer would feel more comfortable to manipulate.
Signed-off-by: NWei Yang <richard.weiyang@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

is_external_interrupt() is not used now and so remove it.
Signed-off-by: NLan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The code tries to pre-allocate *min* number of objects, so it is ok to
return 0 when the kvm_mmu_memory_cache meets the requirement.
Signed-off-by: NWei Yang <richard.weiyang@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Suggested-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NKrish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: NMark Kanda <mark.kanda@oracle.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

On a 64bits machine, struct is naturally aligned with 8 bytes. Since
kvm_mmu_page member *unsync* and *role* are less then 4 bytes, we can
rearrange the sequence to compace the struct.

As the comment shows, *role* and *gfn* are used to key the shadow page. In
order to keep the comment valid, this patch moves the *unsync* up and
exchange the position of *role* and *gfn*.

From /proc/slabinfo, it shows the size of kvm_mmu_page is 8 bytes less and
with one more object per slap after applying this patch.

    # name            <active_objs> <num_objs> <objsize> <objperslab>
    kvm_mmu_page_header      0           0       168         24

    kvm_mmu_page_header      0           0       160         25
Signed-off-by: NWei Yang <richard.weiyang@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

A VMEnter that VMFails (as opposed to VMExits) does not touch host
state beyond registers that are explicitly noted in the VMFail path,
e.g. EFLAGS.  Host state does not need to be loaded because VMFail
is only signaled for consistency checks that occur before the CPU
starts to load guest state, i.e. there is no need to restore any
state as nothing has been modified.  But in the case where a VMFail
is detected by hardware and not by KVM (due to deferring consistency
checks to hardware), KVM has already loaded some amount of guest
state.  Luckily, "loaded" only means loaded to KVM's software model,
i.e. vmcs01 has not been modified.  So, unwind our software model to
the pre-VMEntry host state.

Not restoring host state in this VMFail path leads to a variety of
failures because we end up with stale data in vcpu->arch, e.g. CR0,
CR4, EFER, etc... will all be out of sync relative to vmcs01.  Any
significant delta in the stale data is all but guaranteed to crash
L1, e.g. emulation of SMEP, SMAP, UMIP, WP, etc... will be wrong.

An alternative to this "soft" reload would be to load host state from
vmcs12 as if we triggered a VMExit (as opposed to VMFail), but that is
wildly inconsistent with respect to the VMX architecture, e.g. an L1
VMM with separate VMExit and VMFail paths would explode.

Note that this approach does not mean KVM is 100% accurate with
respect to VMX hardware behavior, even at an architectural level
(the exact order of consistency checks is microarchitecture specific).
But 100% emulation accuracy isn't the goal (with this patch), rather
the goal is to be consistent in the information delivered to L1, e.g.
a VMExit should not fall-through VMENTER, and a VMFail should not jump
to HOST_RIP.

This technically reverts commit "5af41573 (KVM: nVMX: Fix mmu
context after VMLAUNCH/VMRESUME failure)", but retains the core
aspects of that patch, just in an open coded form due to the need to
pull state from vmcs01 instead of vmcs12.  Restoring host state
resolves a variety of issues introduced by commit "4f350c6d
(kvm: nVMX: Handle deferred early VMLAUNCH/VMRESUME failure properly)",
which remedied the incorrect behavior of treating VMFail like VMExit
but in doing so neglected to restore arch state that had been modified
prior to attempting nested VMEnter.

A sample failure that occurs due to stale vcpu.arch state is a fault
of some form while emulating an LGDT (due to emulated UMIP) from L1
after a failed VMEntry to L3, in this case when running the KVM unit
test test_tpr_threshold_values in L1.  L0 also hits a WARN in this
case due to a stale arch.cr4.UMIP.

L1:
  BUG: unable to handle kernel paging request at ffffc90000663b9e
  PGD 276512067 P4D 276512067 PUD 276513067 PMD 274efa067 PTE 8000000271de2163
  Oops: 0009 [#1] SMP
  CPU: 5 PID: 12495 Comm: qemu-system-x86 Tainted: G        W         4.18.0-rc2+ #2
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:native_load_gdt+0x0/0x10

  ...

  Call Trace:
   load_fixmap_gdt+0x22/0x30
   __vmx_load_host_state+0x10e/0x1c0 [kvm_intel]
   vmx_switch_vmcs+0x2d/0x50 [kvm_intel]
   nested_vmx_vmexit+0x222/0x9c0 [kvm_intel]
   vmx_handle_exit+0x246/0x15a0 [kvm_intel]
   kvm_arch_vcpu_ioctl_run+0x850/0x1830 [kvm]
   kvm_vcpu_ioctl+0x3a1/0x5c0 [kvm]
   do_vfs_ioctl+0x9f/0x600
   ksys_ioctl+0x66/0x70
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x4f/0x100
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

L0:
  WARNING: CPU: 2 PID: 3529 at arch/x86/kvm/vmx.c:6618 handle_desc+0x28/0x30 [kvm_intel]
  ...
  CPU: 2 PID: 3529 Comm: qemu-system-x86 Not tainted 4.17.2-coffee+ #76
  Hardware name: Intel Corporation Kabylake Client platform/KBL S
  RIP: 0010:handle_desc+0x28/0x30 [kvm_intel]

  ...

  Call Trace:
   kvm_arch_vcpu_ioctl_run+0x863/0x1840 [kvm]
   kvm_vcpu_ioctl+0x3a1/0x5c0 [kvm]
   do_vfs_ioctl+0x9f/0x5e0
   ksys_ioctl+0x66/0x70
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x49/0xf0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 5af41573 (KVM: nVMX: Fix mmu context after VMLAUNCH/VMRESUME failure)
Fixes: 4f350c6d (kvm: nVMX: Handle deferred early VMLAUNCH/VMRESUME failure properly)
Cc: Jim Mattson <jmattson@google.com>
Cc: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim KrÄmář <rkrcmar@redhat.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

According to volume 3 of the SDM, bits 63:15 and 12:4 of the exit
qualification field for debug exceptions are reserved (cleared to
0). However, the SDM is incorrect about bit 16 (corresponding to
DR6.RTM). This bit should be set if a debug exception (#DB) or a
breakpoint exception (#BP) occurred inside an RTM region while
advanced debugging of RTM transactional regions was enabled. Note that
this is the opposite of DR6.RTM, which "indicates (when clear) that a
debug exception (#DB) or breakpoint exception (#BP) occurred inside an
RTM region while advanced debugging of RTM transactional regions was
enabled."

There is still an issue with stale DR6 bits potentially being
misreported for the current debug exception.  DR6 should not have been
modified before vectoring the #DB exception, and the "new DR6 bits"
should be available somewhere, but it was and they aren't.

Fixes: b96fb439 ("KVM: nVMX: fixes to nested virt interrupt injection")
Signed-off-by: NJim Mattson <jmattson@google.com>
Reviewed-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Let's add the 40 PA-bit versions of the VM modes, that AArch64
should have been using, so we can extend the dirty log test without
breaking things.
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

While we're messing with the code for the port and to support guest
page sizes that are less than the host page size, we also make some
code formatting cleanups and apply sync_global_to_guest().
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Rename VM_MODE_FLAT48PG to be more descriptive of its config and add a
new config that has the same parameters, except with 64K pages.
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This code adds VM and VCPU setup code for the VM_MODE_FLAT48PG mode.
The VM_MODE_FLAT48PG isn't yet fully supportable, as it defines the
guest physical address limit as 52-bits, and KVM currently only
supports guests with up to 40-bit physical addresses (see
KVM_PHYS_SHIFT). VM_MODE_FLAT48PG will work fine, though, as long as
no >= 40-bit physical addresses are used.
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Tidy up kvm-util code: code/comment formatting, remove unused code,
and move x86 specific code out. We also move vcpu_dump() out of
common code, because not all arches (AArch64) have KVM_GET_REGS.
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Rework the guest exit to userspace code to generalize the concept
into what it is, a "hypercall to userspace", and provide two
implementations of it: the PortIO version currently used, but only
useable by x86, and an MMIO version that other architectures (except
s390) can use.
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Guest code may want to call functions that have variable arguments.
To do so, we either need to compile with -mno-sse or enable SSE in
the VCPUs. As it should be pretty safe to turn on the feature, and
-mno-sse would make linking test code with standard libraries
difficult, we choose the feature enabling.
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

In cloud environment, lapic_timer_advance_ns is needed to be tuned for every CPU
generations, and every host kernel versions(the kvm-unit-tests/tscdeadline_latency.flat
is 5700 cycles for upstream kernel and 9600 cycles for our 3.10 product kernel,
both preemption_timer=N, Skylake server).

This patch adds the capability to automatically tune lapic_timer_advance_ns
step by step, the initial value is 1000ns as 'commit d0659d94 ("KVM: x86:
add option to advance tscdeadline hrtimer expiration")' recommended, it will be
reduced when it is too early, and increased when it is too late. The guest_tsc
and tsc_deadline are hard to equal, so we assume we are done when the delta
is within a small scope e.g. 100 cycles. This patch reduces latency
(kvm-unit-tests/tscdeadline_latency, busy waits, preemption_timer enabled)
from ~2600 cyles to ~1200 cyles on our Skylake server.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: NWanpeng Li <wanpengli@tencent.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If L1 uses VPID, it expects TLB to not be flushed on L1<->L2
transitions. However, code currently flushes TLB nonetheless if we
didn't allocate a vpid02 for L2. As in this case,
vmcs02->vpid == vmcs01->vpid == vmx->vpid.

But, if L1 uses EPT, TLB entires populated by L2 are tagged with EPTP02
while TLB entries populated by L1 are tagged with EPTP01.
Therefore, we can also avoid TLB flush if L1 uses VPID and EPT.
Reviewed-by: NMihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: NDarren Kenny <darren.kenny@oracle.com>
Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

All VPID12s used on a given L1 vCPU is translated to a single
VPID02 (vmx->nested.vpid02 or vmx->vpid). Therefore, on L1->L2 VMEntry,
we need to invalidate linear and combined mappings tagged by
VPID02 in case L1 uses VPID and vmcs12->vpid was changed since
last L1->L2 VMEntry.

However, current code invalidates the wrong mappings as it calls
__vmx_flush_tlb() with invalidate_gpa parameter set to true which will
result in invalidating combined and guest-physical mappings tagged with
active EPTP which is EPTP01.

Similarly, INVVPID emulation have the exact same issue.

Fix both issues by just setting invalidate_gpa parameter to false which
will result in invalidating linear and combined mappings tagged with
given VPID02 as required.
Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: NMark Kanda <mark.kanda@oracle.com>
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

In case L0 didn't allocate vmx->nested.vpid02 for L2,
vmcs02->vpid is set to vmx->vpid.
Consider this case when emulating L1 INVVPID in L0.
Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: NMark Kanda <mark.kanda@oracle.com>
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If L1 and L2 share VPID (because L1 don't use VPID or we haven't allocated
a vpid02), we need to flush TLB on L1<->L2 transitions.

Before this patch, this TLB flushing was done by vmx_flush_tlb().
If L0 use EPT, this will translate into INVEPT(active_eptp);
However, if L1 use EPT, in L1->L2 VMEntry, active EPTP is EPTP01 but
TLB entries populated by L2 are tagged with EPTP02.
Therefore we should delay vmx_flush_tlb() until active_eptp is EPTP02.

To achieve this, instead of directly calling vmx_flush_tlb() we request
it to be called by KVM_REQ_TLB_FLUSH which is evaluated after
KVM_REQ_LOAD_CR3 which sets the active_eptp to EPTP02 as required.

Similarly, on L2->L1 VMExit, active EPTP is EPTP02 but TLB entries
populated by L1 are tagged with EPTP01 and therefore we should delay
vmx_flush_tlb() until active_eptp is EPTP01.
Reviewed-by: NMihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: NDarren Kenny <darren.kenny@oracle.com>
Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The KVM_GUEST_CR0_MASK macro tracks CR0 bits that are forced to zero
by the VMX architecture, i.e. CR0.{NW,CD} must always be zero in the
hardware CR0 post-VMXON.  Rename the macro to clarify its purpose,
be consistent with KVM_VM_CR0_ALWAYS_ON and avoid confusion with the
CR0_GUEST_HOST_MASK field.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Merge tag 'kvm-s390-next-4.20-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

KVM: s390/vfio-ap: Fixes and enhancements for vfio-ap

- add tracing
- fix a locking bug
- make local functions and data static

Merge tag 'kvm-ppc-next-4.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD

PPC KVM update for 4.20.

The major new feature here is nested HV KVM support.  This allows the
HV KVM module to load inside a radix guest on POWER9 and run radix
guests underneath it.  These nested guests can run in supervisor mode
and don't require any additional instructions to be emulated, unlike
with PR KVM, and so performance is much better than with PR KVM, and
is very close to the performance of a non-nested guest.  A nested
hypervisor (a guest with nested guests) can be migrated to another
host and will bring all its nested guests along with it.  A nested
guest can also itself run guests, and so on down to any desired depth
of nesting.

Apart from that there are a series of updates for IOMMU handling from
Alexey Kardashevskiy, a "one VM per core" mode for HV KVM for
security-paranoid applications, and a small fix for PR KVM.

This adds a KVM_PPC_NO_HASH flag to the flags field of the
kvm_ppc_smmu_info struct, and arranges for it to be set when
running as a nested hypervisor, as an unambiguous indication
to userspace that HPT guests are not supported.  Reporting the
KVM_CAP_PPC_MMU_HASH_V3 capability as false could be taken as
indicating only that the new HPT features in ISA V3.0 are not
supported, leaving it ambiguous whether pre-V3.0 HPT features
are supported.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>

With this, userspace can enable a KVM-HV guest to run nested guests
under it.

The administrator can control whether any nested guests can be run;
setting the "nested" module parameter to false prevents any guests
becoming nested hypervisors (that is, any attempt to enable the nested
capability on a guest will fail).  Guests which are already nested
hypervisors will continue to be so.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>

This merges in the "ppc-kvm" topic branch of the powerpc tree to get a
series of commits that touch both general arch/powerpc code and KVM
code.  These commits will be merged both via the KVM tree and the
powerpc tree.
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>

This adds a list of valid shadow PTEs for each nested guest to
the 'radix' file for the guest in debugfs.  This can be useful for
debugging.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

With this, the KVM-HV module can be loaded in a guest running under
KVM-HV, and if the hypervisor supports nested virtualization, this
guest can now act as a nested hypervisor and run nested guests.

This also adds some checks to inform userspace that HPT guests are not
supported by nested hypervisors (by returning false for the
KVM_CAP_PPC_MMU_HASH_V3 capability), and to prevent userspace from
configuring a guest to use HPT mode.
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The hcall H_ENTER_NESTED takes two parameters: the address in L1 guest
memory of a hv_regs struct and the address of a pt_regs struct.  The
hcall requests the L0 hypervisor to use the register values in these
structs to run a L2 guest and to return the exit state of the L2 guest
in these structs.  These are in the endianness of the L1 guest, rather
than being always big-endian as is usually the case for PAPR
hypercalls.

This is convenient because it means that the L1 guest can pass the
address of the regs field in its kvm_vcpu_arch struct.  This also
improves performance slightly by avoiding the need for two copies of
the pt_regs struct.

When reading/writing these structures, this patch handles the case
where the endianness of the L1 guest differs from that of the L0
hypervisor, by byteswapping the structures after reading and before
writing them back.

Since all the fields of the pt_regs are of the same type, i.e.,
unsigned long, we treat it as an array of unsigned longs.  The fields
of struct hv_guest_state are not all the same, so its fields are
byteswapped individually.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

restore_hv_regs() is used to copy the hv_regs L1 wants to set to run the
nested (L2) guest into the vcpu structure. We need to sanitise these
values to ensure we don't let the L1 guest hypervisor do things we don't
want it to.

We don't let data address watchpoints or completed instruction address
breakpoints be set to match in hypervisor state.

We also don't let L1 enable features in the hypervisor facility status
and control register (HFSCR) for L2 which we have disabled for L1. That
is L2 will get the subset of features which the L0 hypervisor has
enabled for L1 and the features L1 wants to enable for L2. This could
mean we give L1 a hypervisor facility unavailable interrupt for a
facility it thinks it has enabled, however it shouldn't have enabled a
facility it itself doesn't have for the L2 guest.

We sanitise the registers when copying in the L2 hv_regs. We don't need
to sanitise when copying back the L1 hv_regs since these shouldn't be
able to contain invalid values as they're just what was copied out.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This adds a one-reg register identifier which can be used to read and
set the virtual PTCR for the guest.  This register identifies the
address and size of the virtual partition table for the guest, which
contains information about the nested guests under this guest.

Migrating this value is the only extra requirement for migrating a
guest which has nested guests (assuming of course that the destination
host supports nested virtualization in the kvm-hv module).
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

When running as a nested hypervisor, this avoids reading hypervisor
privileged registers (specifically HFSCR, LPIDR and LPCR) at startup;
instead reasonable default values are used.  This also avoids writing
LPIDR in the single-vcpu entry/exit path.

Also, this removes the check for CPU_FTR_HVMODE in kvmppc_mmu_hv_init()
since its only caller already checks this.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This is only done at level 0, since only level 0 knows which physical
CPU a vcpu is running on.  This does for nested guests what L0 already
did for its own guests, which is to flush the TLB on a pCPU when it
goes to run a vCPU there, and there is another vCPU in the same VM
which previously ran on this pCPU and has now started to run on another
pCPU.  This is to handle the situation where the other vCPU touched
a mapping, moved to another pCPU and did a tlbiel (local-only tlbie)
on that new pCPU and thus left behind a stale TLB entry on this pCPU.

This introduces a limit on the the vcpu_token values used in the
H_ENTER_NESTED hcall -- they must now be less than NR_CPUS.

[paulus@ozlabs.org - made prev_cpu array be short[] to reduce
 memory consumption.]
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This adds code to call the H_TLB_INVALIDATE hypercall when running as
a guest, in the cases where we need to invalidate TLBs (or other MMU
caches) as part of managing the mappings for a nested guest.  Calling
H_TLB_INVALIDATE lets the nested hypervisor inform the parent
hypervisor about changes to partition-scoped page tables or the
partition table without needing to do hypervisor-privileged tlbie
instructions.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

When running a nested (L2) guest the guest (L1) hypervisor will use
the H_TLB_INVALIDATE hcall when it needs to change the partition
scoped page tables or the partition table which it manages.  It will
use this hcall in the situations where it would use a partition-scoped
tlbie instruction if it were running in hypervisor mode.

The H_TLB_INVALIDATE hcall can invalidate different scopes:

Invalidate TLB for a given target address:
- This invalidates a single L2 -> L1 pte
- We need to invalidate any L2 -> L0 shadow_pgtable ptes which map the L2
  address space which is being invalidated. This is because a single
  L2 -> L1 pte may have been mapped with more than one pte in the
  L2 -> L0 page tables.

Invalidate the entire TLB for a given LPID or for all LPIDs:
- Invalidate the entire shadow_pgtable for a given nested guest, or
  for all nested guests.

Invalidate the PWC (page walk cache) for a given LPID or for all LPIDs:
- We don't cache the PWC, so nothing to do.

Invalidate the entire TLB, PWC and partition table for a given/all LPIDs:
- Here we re-read the partition table entry and remove the nested state
  for any nested guest for which the first doubleword of the partition
  table entry is now zero.

The H_TLB_INVALIDATE hcall takes as parameters the tlbie instruction
word (of which only the RIC, PRS and R fields are used), the rS value
(giving the lpid, where required) and the rB value (giving the IS, AP
and EPN values).

[paulus@ozlabs.org - adapted to having the partition table in guest
memory, added the H_TLB_INVALIDATE implementation, removed tlbie
instruction emulation, reworded the commit message.]
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>