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Currently privileged-state guest will be run with TM disabled.
Although the privileged-state guest cannot initiate a new transaction,
it can use tabort to terminate its problem state's transaction.
So it is still necessary to emulate tabort. for privileged-state guest.
Tested with:
https://github.com/justdoitqd/publicFiles/blob/master/test_tabort.c
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This patch adds host emulation when guest PR KVM executes "trechkpt.",
which is a privileged instruction and will trap into host.
We firstly copy vcpu ongoing content into vcpu tm checkpoint
content, then perform kvmppc_restore_tm_pr() to do trechkpt.
with updated vcpu tm checkpoint values.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This patch adds support for "treclaim." emulation when PR KVM guest
executes treclaim. and traps to host.
We will firstly do treclaim. and save TM checkpoint. Then it is
necessary to update vcpu current reg content with checkpointed vals.
When rfid into guest again, those vcpu current reg content (now the
checkpoint vals) will be loaded into regs.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Currently kvmppc_handle_fac() will not update NV GPRs and thus it can
return with GUEST_RESUME.
However PR KVM guest always disables MSR_TM bit in privileged state.
If PR privileged-state guest is trying to read TM SPRs, it will
trigger TM facility unavailable exception and fall into
kvmppc_handle_fac(). Then the emulation will be done by
kvmppc_core_emulate_mfspr_pr(). The mfspr instruction can include a
RT with NV reg. So it is necessary to restore NV GPRs at this case, to
reflect the update to NV RT.
This patch make kvmppc_handle_fac() return GUEST_RESUME_NV for TM
facility unavailable exceptions in guest privileged state.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Currently the kernel doesn't use transaction memory.
And there is an issue for privileged state in the guest that:
tbegin/tsuspend/tresume/tabort TM instructions can impact MSR TM bits
without trapping into the PR host. So following code will lead to a
false mfmsr result:
tbegin <- MSR bits update to Transaction active.
beq <- failover handler branch
mfmsr <- still read MSR bits from magic page with
transaction inactive.
It is not an issue for non-privileged guest state since its mfmsr is
not patched with magic page and will always trap into the PR host.
This patch will always fail tbegin attempt for privileged state in the
guest, so that the above issue is prevented. It is benign since
currently (guest) kernel doesn't initiate a transaction.
Test case:
https://github.com/justdoitqd/publicFiles/blob/master/test_tbegin_pr.c
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The mfspr/mtspr on TM SPRs(TEXASR/TFIAR/TFHAR) are non-privileged
instructions and can be executed by PR KVM guest in problem state
without trapping into the host. We only emulate mtspr/mfspr
texasr/tfiar/tfhar in guest PR=0 state.
When we are emulating mtspr tm sprs in guest PR=0 state, the emulation
result needs to be visible to guest PR=1 state. That is, the actual TM
SPR val should be loaded into actual registers.
We already flush TM SPRs into vcpu when switching out of CPU, and load
TM SPRs when switching back.
This patch corrects mfspr()/mtspr() emulation for TM SPRs to make the
actual source/dest be the actual TM SPRs.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The math registers will be saved into vcpu->arch.fp/vr and corresponding
vcpu->arch.fp_tm/vr_tm area.
We flush or giveup the math regs into vcpu->arch.fp/vr before saving
transaction. After transaction is restored, the math regs will be loaded
back into regs.
If there is a FP/VEC/VSX unavailable exception during transaction active
state, the math checkpoint content might be incorrect and we need to do
treclaim./load the correct checkpoint val/trechkpt. sequence to retry the
transaction. That will make our solution complicated. To solve this issue,
we always make the hardware guest MSR math bits (shadow_msr) consistent
with the MSR val which guest sees (kvmppc_get_msr()) when guest msr is
with tm enabled. Then all FP/VEC/VSX unavailable exception can be delivered
to guest and guest handles the exception by itself.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The transaction memory checkpoint area save/restore behavior is
triggered when VCPU qemu process is switching out/into CPU, i.e.
at kvmppc_core_vcpu_put_pr() and kvmppc_core_vcpu_load_pr().
MSR TM active state is determined by TS bits:
active: 10(transactional) or 01 (suspended)
inactive: 00 (non-transactional)
We don't "fake" TM functionality for guest. We "sync" guest virtual
MSR TM active state(10 or 01) with shadow MSR. That is to say,
we don't emulate a transactional guest with a TM inactive MSR.
TM SPR support(TFIAR/TFAR/TEXASR) has already been supported by
commit 9916d57e64 ("KVM: PPC: Book3S PR: Expose TM registers").
Math register support (FPR/VMX/VSX) will be done at subsequent
patch.
Whether TM context need to be saved/restored can be determined
by kvmppc_get_msr() TM active state:
* TM active - save/restore TM context
* TM inactive - no need to do so and only save/restore
TM SPRs.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Suggested-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This patch adds 2 new APIs, kvmppc_save_tm_sprs() and
kvmppc_restore_tm_sprs(), for the purpose of TEXASR/TFIAR/TFHAR
save/restore.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This patch adds 2 new APIs: kvmppc_copyto_vcpu_tm() and
kvmppc_copyfrom_vcpu_tm(). These 2 APIs will be used to copy from/to TM
data between VCPU_TM/VCPU area.
PR KVM will use these APIs for treclaim. or trechkpt. emulation.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
PR KVM host usually runs with TM enabled in its host MSR value, and
with non-transactional TS value.
When a guest with TM active traps into PR KVM host, the rfid at the
tail of kvmppc_interrupt_pr() will try to switch TS bits from
S0 (Suspended & TM disabled) to N1 (Non-transactional & TM enabled).
That will leads to TM Bad Thing interrupt.
This patch manually sets target TS bits unchanged to avoid this
exception.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
According to ISA specification for RFID, in MSR TM disabled and TS
suspended state (S0), if the target MSR is TM disabled and TS state is
inactive (N0), rfid should suppress this update.
This patch makes the RFID emulation of PR KVM consistent with this.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
MSR TS bits can be modified with non-privileged instruction such as
tbegin./tend. That means guest can change MSR value "silently" without
notifying host.
It is necessary to sync the TM bits to host so that host can calculate
shadow msr correctly.
Note, privileged mode in the guest will always fail transactions so we
only take care of problem state mode in the guest.
The logic is put into kvmppc_copy_from_svcpu() so that
kvmppc_handle_exit_pr() can use correct MSR TM bits even when preemption
occurs.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
PowerPC TM functionality needs MSR TM/TS bits support in hardware level.
Guest TM functionality can not be emulated with "fake" MSR (msr in magic
page) TS bits.
This patch syncs TM/TS bits in shadow_msr with the MSR value in magic
page, so that the MSR TS value which guest sees is consistent with actual
MSR bits running in guest.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This patch simulates interrupt behavior per Power ISA while injecting
interrupt in PR KVM:
- When interrupt happens, transactional state should be suspended.
kvmppc_mmu_book3s_64_reset_msr() will be invoked when injecting an
interrupt. This patch performs this ISA logic in
kvmppc_mmu_book3s_64_reset_msr().
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Currently __kvmppc_save/restore_tm() APIs can only be invoked from
assembly function. This patch adds C function wrappers for them so
that they can be safely called from C function.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
kvmppc_save_tm() invokes store_fp_state/store_vr_state(). So it is
mandatory to turn on FP/VSX/VMX MSR bits for its execution, just
like what kvmppc_restore_tm() did.
Previously HV KVM has turned the bits on outside of function
kvmppc_save_tm(). Now we include this bit change in kvmppc_save_tm()
so that the logic is cleaner. And PR KVM can reuse it later.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
HV KVM and PR KVM need different MSR source to indicate whether
treclaim. or trecheckpoint. is necessary.
This patch add new parameter (guest MSR) for these kvmppc_save_tm/
kvmppc_restore_tm() APIs:
- For HV KVM, it is VCPU_MSR
- For PR KVM, it is current host MSR or VCPU_SHADOW_SRR1
This enhancement enables these 2 APIs to be reused by PR KVM later.
And the patch keeps HV KVM logic unchanged.
This patch also reworks kvmppc_save_tm()/kvmppc_restore_tm() to
have a clean ABI: r3 for vcpu and r4 for guest_msr.
During kvmppc_save_tm/kvmppc_restore_tm(), the R1 need to be saved
or restored. Currently the R1 is saved into HSTATE_HOST_R1. In PR
KVM, we are going to add a C function wrapper for
kvmppc_save_tm/kvmppc_restore_tm() where the R1 will be incremented
with added stackframe and save into HSTATE_HOST_R1. There are several
places in HV KVM to load HSTATE_HOST_R1 as R1, and we don't want to
bring risk or confusion by TM code.
This patch will use HSTATE_SCRATCH2 to save/restore R1 in
kvmppc_save_tm/kvmppc_restore_tm() to avoid future confusion, since
the r1 is actually a temporary/scratch value to be saved/stored.
[paulus@ozlabs.org - rebased on top of 7b0e827c69 ("KVM: PPC: Book3S HV:
Factor fake-suspend handling out of kvmppc_save/restore_tm", 2018-05-30)]
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
It is a simple patch just for moving kvmppc_save_tm/kvmppc_restore_tm()
functionalities to tm.S. There is no logic change. The reconstruct of
those APIs will be done in later patches to improve readability.
It is for preparation of reusing those APIs on both HV/PR PPC KVM.
Some slight change during move the functions includes:
- surrounds some HV KVM specific code with CONFIG_KVM_BOOK3S_HV_POSSIBLE
for compilation.
- use _GLOBAL() to define kvmppc_save_tm/kvmppc_restore_tm()
[paulus@ozlabs.org - rebased on top of 7b0e827c69 ("KVM: PPC: Book3S HV:
Factor fake-suspend handling out of kvmppc_save/restore_tm", 2018-05-30)]
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This merges in the ppc-kvm topic branch of the powerpc repository
to get some changes on which future patches will depend, in particular
some new exports and TEXASR bit definitions.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This splits out the handling of "fake suspend" mode, part of the
hypervisor TM assist code for POWER9, and puts almost all of it in
new kvmppc_save_tm_hv and kvmppc_restore_tm_hv functions. The new
functions branch to kvmppc_save/restore_tm if the CPU does not
require hypervisor TM assistance.
With this, it will be more straightforward to move kvmppc_save_tm and
kvmppc_restore_tm to another file and use them for transactional
memory support in PR KVM. Additionally, it also makes the code a
bit clearer and reduces the number of feature sections.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Currently, PR KVM does not implement the configure_mmu operation, and
so the KVM_PPC_CONFIGURE_V3_MMU ioctl always fails with an EINVAL
error. This causes recent kernels to fail to boot as a PR KVM guest
on POWER9, since recent kernels booted in HPT mode do the
H_REGISTER_PROC_TBL hypercall, which causes userspace (QEMU) to do
KVM_PPC_CONFIGURE_V3_MMU, which fails.
This implements a minimal configure_mmu operation for PR KVM. It
succeeds only if the MMU is being configured for HPT mode and no
process table is being registered. This is enough to get recent
kernels to boot as a PR KVM guest.
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This patch exports tm_enable()/tm_disable/tm_abort() APIs, which
will be used for PR KVM transactional memory logic.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patches add some macros for CR0/TEXASR bits so that PR KVM TM
logic (tbegin./treclaim./tabort.) can make use of them later.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
PR KVM will need to reuse msr_check_and_set().
This patch exports this API for reuse.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch reimplements LOAD_VMX/STORE_VMX MMIO emulation with
analyse_instr() input. When emulating the store, the VMX reg will need to
be flushed so that the right reg val can be retrieved before writing to
IO MEM.
This patch also adds support for lvebx/lvehx/lvewx/stvebx/stvehx/stvewx
MMIO emulation. To meet the requirement of handling different element
sizes, kvmppc_handle_load128_by2x64()/kvmppc_handle_store128_by2x64()
were replaced with kvmppc_handle_vmx_load()/kvmppc_handle_vmx_store().
The framework used is similar to VSX instruction MMIO emulation.
Suggested-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
VSX MMIO emulation uses mmio_vsx_copy_type to represent VSX emulated
element size/type, such as KVMPPC_VSX_COPY_DWORD_LOAD, etc. This
patch expands mmio_vsx_copy_type to cover VMX copy type, such as
KVMPPC_VMX_COPY_BYTE(stvebx/lvebx), etc. As a result,
mmio_vsx_copy_type is also renamed to mmio_copy_type.
It is a preparation for reimplementing VMX MMIO emulation.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This patch reimplements LOAD_VSX/STORE_VSX instruction MMIO emulation with
analyse_instr() input. It utilizes VSX_FPCONV/VSX_SPLAT/SIGNEXT exported
by analyse_instr() and handle accordingly.
When emulating VSX store, the VSX reg will need to be flushed so that
the right reg val can be retrieved before writing to IO MEM.
[paulus@ozlabs.org - mask the register number to 5 bits.]
Suggested-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This patch reimplements LOAD_FP/STORE_FP instruction MMIO emulation with
analyse_instr() input. It utilizes the FPCONV/UPDATE properties exported by
analyse_instr() and invokes kvmppc_handle_load(s)/kvmppc_handle_store()
accordingly.
For FP store MMIO emulation, the FP regs need to be flushed firstly so
that the right FP reg vals can be read from vcpu->arch.fpr, which will
be stored into MMIO data.
Suggested-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Currently HV will save math regs(FP/VEC/VSX) when trap into host. But
PR KVM will only save math regs when qemu task switch out of CPU, or
when returning from qemu code.
To emulate FP/VEC/VSX mmio load, PR KVM need to make sure that math
regs were flushed firstly and then be able to update saved VCPU
FPR/VEC/VSX area reasonably.
This patch adds giveup_ext() field to KVM ops. Only PR KVM has non-NULL
giveup_ext() ops. kvmppc_complete_mmio_load() can invoke that hook
(when not NULL) to flush math regs accordingly, before updating saved
register vals.
Math regs flush is also necessary for STORE, which will be covered
in later patch within this patch series.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This patch reimplements non-SIMD LOAD/STORE instruction MMIO emulation
with analyse_instr() input. It utilizes the BYTEREV/UPDATE/SIGNEXT
properties exported by analyse_instr() and invokes
kvmppc_handle_load(s)/kvmppc_handle_store() accordingly.
It also moves CACHEOP type handling into the skeleton.
instruction_type within kvm_ppc.h is renamed to avoid conflict with
sstep.h.
Suggested-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Some VSX instructions like lxvwsx will splat word into VSR. This patch
adds a new VSX copy type KVMPPC_VSX_COPY_WORD_LOAD_DUMP to support this.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This relaxes the restriction on using PR KVM on POWER9. The existing
code does work inside a guest partition running in HPT mode, because
hypercalls such as H_ENTER use the old HPTE format, not the new
format used by POWER9, and so no change to PR KVM's HPT manipulation
code is required. PR KVM will still refuse to run if the kernel is
using radix translation or if it is running bare-metal.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
It's possible to take a SRESET or MCE in these paths due to a bug
in the host code or a NMI IPI, etc. A recent bug attempting to load
a virtual address from real mode gave th complete but cryptic error,
abridged:
Oops: Bad interrupt in KVM entry/exit code, sig: 6 [#1]
LE SMP NR_CPUS=2048 NUMA PowerNV
CPU: 53 PID: 6582 Comm: qemu-system-ppc Not tainted
NIP: c0000000000155ac LR: c0000000000c2430 CTR: c000000000015580
REGS: c000000fff76dd80 TRAP: 0200 Not tainted
MSR: 9000000000201003 <SF,HV,ME,RI,LE> CR: 48082222 XER: 00000000
CFAR: 0000000102900ef0 DAR: d00017fffd941a28 DSISR: 00000040 SOFTE: 3
NIP [c0000000000155ac] perf_trace_tlbie+0x2c/0x1a0
LR [c0000000000c2430] do_tlbies+0x230/0x2f0
Sending the NMIs through the Linux handlers gives a nicer output:
Severe Machine check interrupt [Not recovered]
NIP [c0000000000155ac]: perf_trace_tlbie+0x2c/0x1a0
Initiator: CPU
Error type: Real address [Load (bad)]
Effective address: d00017fffcc01a28
opal: Machine check interrupt unrecoverable: MSR(RI=0)
opal: Hardware platform error: Unrecoverable Machine Check exception
CPU: 0 PID: 6700 Comm: qemu-system-ppc Tainted: G M
NIP: c0000000000155ac LR: c0000000000c23c0 CTR: c000000000015580
REGS: c000000fff9e9d80 TRAP: 0200 Tainted: G M
MSR: 9000000000201001 <SF,HV,ME,LE> CR: 48082222 XER: 00000000
CFAR: 000000010cbc1a30 DAR: d00017fffcc01a28 DSISR: 00000040 SOFTE: 3
NIP [c0000000000155ac] perf_trace_tlbie+0x2c/0x1a0
LR [c0000000000c23c0] do_tlbies+0x1c0/0x280
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
When CONFIG_RELOCATABLE=n, the Linux real mode interrupt handlers call
into KVM using real address. This needs to be translated to the kernel
linear effective address before the MMU is switched on.
kvmppc_bad_host_intr misses adding these bits, so when it is used to
handle a system reset interrupt (that always gets delivered in real
mode), it results in an instruction access fault immediately after
the MMU is turned on.
Fix this by ensuring the top 2 address bits are set when the MMU is
turned on.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Adding the write bit and RC bits to pte permissions does not require a
pte clear and flush. There should not be other bits changed here,
because restricting access or changing the PFN must have already
invalidated any existing ptes (otherwise the race is already lost).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
When the radix fault handler has no page from the process address
space (e.g., for IO memory), it looks up the process pte and sets
partition table pte using that to get attributes like CI and guarded.
If the process table entry is to be writable, set _PAGE_DIRTY as well
to avoid an RC update. If not, then ensure _PAGE_DIRTY does not come
across. Set _PAGE_ACCESSED as well to avoid RC update.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The radix guest code can has fewer restrictions about what context it
can run in, so move this flushing out of assembly and have it use the
Linux TLB flush implementations introduced previously.
This allows powerpc:tlbie trace events to be used.
This changes the tlbiel sequence to only execute RIC=2 flush once on
the first set flushed, then RIC=0 for the rest of the sets. The end
result of the flush should be unchanged. This matches the local PID
flush pattern that was introduced in a5998fcb92 ("powerpc/mm/radix:
Optimise tlbiel flush all case").
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This has the advantage of consolidating TLB flush code in fewer
places, and it also implements powerpc:tlbie trace events.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
When partition scope mappings are unmapped with kvm_unmap_radix, the
pte is cleared, but the page table structure is left in place. If the
next page fault requests a different page table geometry (e.g., due to
THP promotion or split), kvmppc_create_pte is responsible for changing
the page tables.
When a page table entry is to be converted to a large pte, the page
table entry is cleared, the PWC flushed, then the page table it points
to freed. This will cause pte page tables to leak when a 1GB page is
to replace a pud entry points to a pmd table with pte tables under it:
The pmd table will be freed, but its pte tables will be missed.
Fix this by replacing the simple clear and free code with one that
walks down the page tables and frees children. Care must be taken to
clear the root entry being unmapped then flushing the PWC before
freeing any page tables, as explained in comments.
This requires PWC flush to logically become a flush-all-PWC (which it
already is in hardware, but the KVM API needs to be changed to avoid
confusion).
This code also checks that no unexpected pte entries exist in any page
table being freed, and unmaps those and emits a WARN. This is an
expensive operation for the pte page level, but partition scope
changes are rare, so it's unconditional for now to iron out bugs. It
can be put under a CONFIG option or removed after some time.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
tlbies to an LPAR do not have to be serialised since POWER4/PPC970,
after which the MMU_FTR_LOCKLESS_TLBIE feature was introduced to
avoid tlbie locking.
Since commit c17b98cf60 ("KVM: PPC: Book3S HV: Remove code for
PPC970 processors"), KVM no longer supports processors that do not
have this feature, so the tlbie locking can be removed completely.
A sanity check for the feature is put in kvmppc_mmu_hv_init.
Testing was done on a POWER9 system in HPT mode, with a -smp 32 guest
in HPT mode. 32 instances of the powerpc fork benchmark from selftests
were run with --fork, and the results measured.
Without this patch, total throughput was about 13.5K/sec, and this is
the top of the host profile:
74.52% [k] do_tlbies
2.95% [k] kvmppc_book3s_hv_page_fault
1.80% [k] calc_checksum
1.80% [k] kvmppc_vcpu_run_hv
1.49% [k] kvmppc_run_core
After this patch, throughput was about 51K/sec, with this profile:
21.28% [k] do_tlbies
5.26% [k] kvmppc_run_core
4.88% [k] kvmppc_book3s_hv_page_fault
3.30% [k] _raw_spin_lock_irqsave
3.25% [k] gup_pgd_range
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
When KVM emulates VMX store, it will invoke kvmppc_get_vmx_data() to
retrieve VMX reg val. kvmppc_get_vmx_data() will check mmio_host_swabbed
to decide which double word of vr[] to be used. But the
mmio_host_swabbed can be uninitialized during VMX store procedure:
kvmppc_emulate_loadstore
\- kvmppc_handle_store128_by2x64
\- kvmppc_get_vmx_data
So vcpu->arch.mmio_host_swabbed is not meant to be used at all for
emulation of store instructions, and this patch makes that true for
VMX stores. This patch also initializes mmio_host_swabbed to avoid
possible future problems.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This patch moves nip/ctr/lr/xer registers from scattered places in
kvm_vcpu_arch to pt_regs structure.
cr register is "unsigned long" in pt_regs and u32 in vcpu->arch.
It will need more consideration and may move in later patches.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Current regs are scattered at kvm_vcpu_arch structure and it will
be more neat to organize them into pt_regs structure.
Also it will enable reimplementation of MMIO emulation code with
analyse_instr() later.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This merges in the ppc-kvm topic branch of the powerpc repository
to get some changes on which future patches will depend, in particular
the definitions of various new TLB flushing functions.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Use new return type vm_fault_t for fault handler
in struct vm_operations_struct. For now, this is
just documenting that the function returns a
VM_FAULT value rather than an errno. Once all
instances are converted, vm_fault_t will become
a distinct type.
commit 1c8f422059 ("mm: change return type to
vm_fault_t")
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Although it does not seem possible to break the host by passing bad
parameters when creating a TCE table in KVM, it is still better to get
an early clear indication of that than debugging weird effect this might
bring.
This adds some sanity checks that the page size is 4KB..16GB as this is
what the actual LoPAPR supports and that the window actually fits 64bit
space.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
At the moment we only support in the host the IOMMU page sizes which
the guest is aware of, which is 4KB/64KB/16MB. However P9 does not support
16MB IOMMU pages, 2MB and 1GB pages are supported instead. We can still
emulate bigger guest pages (for example 16MB) with smaller host pages
(4KB/64KB/2MB).
This allows the physical IOMMU pages to use a page size smaller or equal
than the guest visible IOMMU page size.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The other TCE handlers use page shift from the guest visible TCE table
(described by kvmppc_spapr_tce_iommu_table) so let's make H_STUFF_TCE
handlers do the same thing.
This should cause no behavioral change now but soon we will allow
the iommu_table::it_page_shift being different from from the emulated
table page size so this will play a role.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
