- 26 Aug, 2021 14 commits
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Aneesh Kumar K.V authored
Fix make htmldocs related errors with the newly added associativity.rst doc file. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Tested-by: Stephen Rothwell <sfr@canb.auug.org.au> # build test Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210825042447.106219-1-aneesh.kumar@linux.ibm.com
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Michael Ellerman authored
Merge the changes to retire the legacy WR sbc8548 and sbc8641 platforms from Paul. These were sent as a pull request, but I rebased them onto rc2 so as not to pull too many unrelated changes in to my next. Description from Paul's pull request follows: In v2.6.27 (2008, 917f0af9) the sbc8260 support was implicitly retired by not being carried forward through the ppc --> powerpc device tree transition. Then, in v3.6 (2012, b048b4e1) we retired the support for the sbc8560 boards. Next, in v4.18 (2017, 3bc6cf5a) we retired the support for the 2006 vintage sbc834x boards. The sbc8548 and sbc8641d boards were maybe 1-2 years newer than the sbc834x boards, but it is also 3+ years later, so it makes sense to now retire them as well - which is what is done here. These two remaining WR boards were based on the Freescale MPC8548-CDS and the MPC8641D-HPCN reference board implementations. Having had the chance to use these and many other Fsl ref boards, I know this: The Freescale reference boards were typically produced in limited quantity and primarily available to BSP developers and hardware designers, and not likely to have found a 2nd life with hobbyists and/or collectors. It was good to have that BSP code subjected to mainline review and hence also widely available back in the day. But given the above, we should probably also be giving serious consideration to retiring additional similar age/type reference board platforms as well. I've always felt it is important for us to be proactive in retiring old code, since it has a genuine non-zero carrying cost, as described in the 930d52c0 merge log. But for the here and now, we just clean up the remaining BSP code that I had added for SBC platforms. Link: https://lore.kernel.org/r/20210824174209.GB160508@windriver.com
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Paul Gortmaker authored
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Paul Gortmaker authored
The support was for this was added to mainline over 12 years ago, in v2.6.26 [4e8aae89] just around the ppc --> powerpc migration. I believe the board was introduced shortly after the sbc8548 board, making it roughly a 14 year old platform - with the CPU speed and memory size typical for that era. I haven't had one of these boards for several years, and availability was discontinued several years before that. Given that, there is no point in adding a burden to testing coverage that builds all possible defconfigs, so it makes sense to remove it. Of course it will remain in the git history forever, for anyone who happens to find a functional board and wants to tinker with it. Acked-by: Scott Wood <oss@buserror.net> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Paul Gortmaker authored
The support was for this was mainlined 13 years ago, in v2.6.25 [0e0fffe8] just around the ppc --> powerpc migration. I believe the board was introduced a year or two before that, so it is roughly a 15 year old platform - with the CPU speed and memory size that was typical for that era. I haven't had one of these boards for several years, and availability was discontinued several years before that. Given that, there is no point in adding a burden to testing coverage that builds all possible defconfigs, so it makes sense to remove it. Of course it will remain in the git history forever, for anyone who happens to find a functional board and wants to tinker with it. Acked-by: Scott Wood <oss@buserror.net> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Michael Ellerman authored
Merge some KVM patches we are keeping in a topic branch in case there are any merge conflicts that need resolving.
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Christophe Leroy authored
40x and BOOKE don't have MSR_RI therefore all tests involving MSR_RI may be problematic on those plateforms. Create helpers to check or set MSR_RI in regs, and use them in common code. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/c2fb93708196734f4176dda334aaa3055f213b89.1629707037.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
In those hot functions that are called at every interrupt, any saved cycle is worth it. interrupt_exit_user_prepare() and interrupt_exit_kernel_prepare() are called from three places: - From entry_32.S - From interrupt_64.S - From interrupt_exit_user_restart() and interrupt_exit_kernel_restart() In entry_32.S, there are inambiguously called based on MSR_PR: interrupt_return: lwz r4,_MSR(r1) addi r3,r1,STACK_FRAME_OVERHEAD andi. r0,r4,MSR_PR beq .Lkernel_interrupt_return bl interrupt_exit_user_prepare ... .Lkernel_interrupt_return: bl interrupt_exit_kernel_prepare In interrupt_64.S, that's similar: interrupt_return_\srr\(): ld r4,_MSR(r1) andi. r0,r4,MSR_PR beq interrupt_return_\srr\()_kernel interrupt_return_\srr\()_user: /* make backtraces match the _kernel variant */ addi r3,r1,STACK_FRAME_OVERHEAD bl interrupt_exit_user_prepare ... interrupt_return_\srr\()_kernel: addi r3,r1,STACK_FRAME_OVERHEAD bl interrupt_exit_kernel_prepare In interrupt_exit_user_restart() and interrupt_exit_kernel_restart(), MSR_PR is verified respectively by BUG_ON(!user_mode(regs)) and BUG_ON(user_mode(regs)) prior to calling interrupt_exit_user_prepare() and interrupt_exit_kernel_prepare(). The verification in interrupt_exit_user_prepare() and interrupt_exit_kernel_prepare() are therefore useless and can be removed. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Acked-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/385ead49ccb66a259b25fee3eebf0bd4094068f3.1629707037.git.christophe.leroy@csgroup.eu
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Xiongwei Song authored
Use _DEAR to get the offset of dear register in pr_regs for 64e cpus. Signed-off-by: Xiongwei Song <sxwjean@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210807010239.416055-5-sxwjean@me.com
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Xiongwei Song authored
Create an anonymous union for dar and dear regsiters, we can reference dear to get the effective address when CONFIG_4xx=y or CONFIG_BOOKE=y. Otherwise, reference dar. This makes code more clear. Signed-off-by: Xiongwei Song <sxwjean@gmail.com> [mpe: Reword commit title] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210807010239.416055-4-sxwjean@me.com
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Xiongwei Song authored
Use _ESR to get the offset of esr register in pr_regs for 64e cpus. Signed-off-by: Xiongwei Song <sxwjean@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210807010239.416055-3-sxwjean@me.com
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Xiongwei Song authored
Create an anonymous union for dsisr and esr regsiters, we can reference esr to get the exception detail when CONFIG_4xx=y or CONFIG_BOOKE=y. Otherwise, reference dsisr. This makes code more clear. Signed-off-by: Xiongwei Song <sxwjean@gmail.com> [mpe: Reword commit title] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210807010239.416055-2-sxwjean@me.com
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Jordan Niethe authored
Transactional Memory was removed from the architecture in ISA v3.1. For threads running in P8/P9 compatibility mode on P10 a synthetic TM implementation is provided. In this implementation, tbegin. always sets cr0 eq meaning the abort handler is always called. This is not an issue as users of TM are expected to have a fallback non transactional way to make forward progress in the abort handler. The TEXASR indicates if a transaction failure is due to a synthetic implementation. Some of the TM self tests need a non-degenerate TM implementation for their testing to be meaningful so check for a synthetic implementation and skip the test if so. Signed-off-by: Jordan Niethe <jniethe5@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210729041317.366612-2-jniethe5@gmail.com
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Jordan Niethe authored
ISA v3.1 removes TM but includes a synthetic implementation for backwards compatibility. With this implementation, the tests ptrace-tm-spd-gpr and ptrace-tm-gpr should never be able to make any forward progress and eventually should be killed by the timeout. Instead on a P10 running in P9 mode, ptrace_tm_gpr fails like so: test: ptrace_tm_gpr tags: git_version:unknown Starting the child ... ... GPR[27]: 1 Expected: 2 GPR[28]: 1 Expected: 2 GPR[29]: 1 Expected: 2 GPR[30]: 1 Expected: 2 GPR[31]: 1 Expected: 2 [FAIL] Test FAILED on line 98 failure: ptrace_tm_gpr selftests: ptrace-tm-gpr [FAIL] The problem is in the inline assembly of the child. r0 is loaded with a value in the child's transaction abort handler but this register is not included in the clobbers list. This means it is possible that this statement: cptr[1] = 0; which is meant to signal the parent to wait may actually use the value placed into r0 by the inline assembly incorrectly signal the parent to continue. By inspection the same problem is present in ptrace-tm-spd-gpr. Adding r0 to the clobbbers list makes the test fail correctly via a timeout on a P10 running in P8/P9 compatibility mode. Suggested-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Jordan Niethe <jniethe5@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210729041317.366612-1-jniethe5@gmail.com
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- 25 Aug, 2021 23 commits
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Kajol Jain authored
Incase of random sampling, there can be scenarios where Sample Instruction Address Register(SIAR) may not latch to the sampled instruction and could result in the value of 0. In these scenarios it is preferred to return regs->nip. These corner cases are seen in the previous generation (p9) also. Patch adds the check for SIAR value along with regs_use_siar and siar_valid checks so that the function will return regs->nip incase SIAR is zero. Patch drops the code under PPMU_P10_DD1 flag check which handles SIAR 0 case only for Power10 DD1. Fixes: 2ca13a4c ("powerpc/perf: Use regs->nip when SIAR is zero") Signed-off-by: Kajol Jain <kjain@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210818171556.36912-3-kjain@linux.ibm.com
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Kajol Jain authored
Drop the case of returning 0 as instruction pointer since kernel never executes at 0 and userspace almost never does either. Fixes: e6878835 ("powerpc/perf: Sample only if SIAR-Valid bit is set in P7+") Signed-off-by: Kajol Jain <kjain@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210818171556.36912-2-kjain@linux.ibm.com
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Kajol Jain authored
Minor optimization in the 'perf_instruction_pointer' function code by making use of stack siar instead of mfspr. Fixes: 75382aa7 ("powerpc/perf: Move code to select SIAR or pt_regs into perf_read_regs") Signed-off-by: Kajol Jain <kjain@linux.ibm.com> Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210818171556.36912-1-kjain@linux.ibm.com
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Nicholas Piggin authored
This register is not architected and not implemented in POWER9 or 10, it just reads back zeroes for compatibility. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Link: https://lore.kernel.org/r/20210811160134.904987-11-npiggin@gmail.com
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Nicholas Piggin authored
After the L1 saves its PMU SPRs but before loading the L2's PMU SPRs, switch the pmcregs_in_use field in the L1 lppaca to the value advertised by the L2 in its VPA. On the way out of the L2, set it back after saving the L2 PMU registers (if they were in-use). This transfers the PMU liveness indication between the L1 and L2 at the points where the registers are not live. This fixes the nested HV bug for which a workaround was added to the L0 HV by commit 63279eeb ("KVM: PPC: Book3S HV: Always save guest pmu for guest capable of nesting"), which explains the problem in detail. That workaround is no longer required for guests that include this bug fix. Fixes: 360cae31 ("KVM: PPC: Book3S HV: Nested guest entry via hypercall") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Link: https://lore.kernel.org/r/20210811160134.904987-10-npiggin@gmail.com
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Fabiano Rosas authored
vcpu is already anargument so vcpu->arch.trap can be used directly. Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210811160134.904987-9-npiggin@gmail.com
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Fabiano Rosas authored
If the nested hypervisor has no access to a facility because it has been disabled by the host, it should also not be able to see the Hypervisor Facility Unavailable that arises from one of its guests trying to access the facility. This patch turns a HFU that happened in L2 into a Hypervisor Emulation Assistance interrupt and forwards it to L1 for handling. The ones that happened because L1 explicitly disabled the facility for L2 are still let through, along with the corresponding Cause bits in the HFSCR. Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> [np: move handling into kvmppc_handle_nested_exit] Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210811160134.904987-8-npiggin@gmail.com
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Nicholas Piggin authored
When the L0 runs a nested L2, there are several permutations of HFSCR that can be relevant. The HFSCR that the L1 vcpu L1 requested, the HFSCR that the L1 vcpu may use, and the HFSCR that is actually being used to run the L2. The L1 requested HFSCR is not accessible outside the nested hcall handler, so copy that into a new kvm_nested_guest.hfscr field. The permitted HFSCR is taken from the HFSCR that the L1 runs with, which is also not accessible while the hcall is being made. Move this into a new kvm_vcpu_arch.hfscr_permitted field. These will be used by the next patch to improve facility handling for nested guests, and later by facility demand faulting patches. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210811160134.904987-7-npiggin@gmail.com
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Fabiano Rosas authored
As one of the arguments of the H_ENTER_NESTED hypercall, the nested hypervisor (L1) prepares a structure containing the values of various hypervisor-privileged registers with which it wants the nested guest (L2) to run. Since the nested HV runs in supervisor mode it needs the host to write to these registers. To stop a nested HV manipulating this mechanism and using a nested guest as a proxy to access a facility that has been made unavailable to it, we have a routine that sanitises the values of the HV registers before copying them into the nested guest's vcpu struct. However, when coming out of the guest the values are copied as they were back into L1 memory, which means that any sanitisation we did during guest entry will be exposed to L1 after H_ENTER_NESTED returns. This patch alters this sanitisation to have effect on the vcpu->arch registers directly before entering and after exiting the guest, leaving the structure that is copied back into L1 unchanged (except when we really want L1 to access the value, e.g the Cause bits of HFSCR). Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Link: https://lore.kernel.org/r/20210811160134.904987-6-npiggin@gmail.com
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Nicholas Piggin authored
Have the TM softpatch emulation code set up the HFAC interrupt and return -1 in case an instruction was executed with HFSCR bits clear, and have the interrupt exit handler fall through to the HFAC handler. When the L0 is running a nested guest, this ensures the HFAC interrupt is correctly passed up to the L1. The "direct guest" exit handler will turn these into PROGILL program interrupts so functionality in practice will be unchanged. But it's possible an L1 would want to handle these in a different way. Also rearrange the FAC interrupt emulation code to match the HFAC format while here (mainly, adding the FSCR_INTR_CAUSE mask). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210811160134.904987-5-npiggin@gmail.com
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Nicholas Piggin authored
The softpatch interrupt sets HSRR0 to the faulting instruction +4, so it should subtract 4 for the faulting instruction address in the case it is a TM softpatch interrupt (the instruction was not executed) and it was not emulated. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210811160134.904987-4-npiggin@gmail.com
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Nicholas Piggin authored
TM fake-suspend emulation is only used by POWER9. Remove it from the old code path. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210811160134.904987-3-npiggin@gmail.com
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Nicholas Piggin authored
It is possible to create a VCPU without setting the MSR before running it, which results in a warning in kvmhv_vcpu_entry_p9() that MSR_ME is not set. This is pretty harmless because the MSR_ME bit is added to HSRR1 before HRFID to guest, and a normal qemu guest doesn't hit it. Initialise the vcpu MSR with MSR_ME set. Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210811160134.904987-2-npiggin@gmail.com
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Christophe Leroy authored
Force the eh flag at 0 on PPC32. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1fc81f07cabebb875b963e295408cc3dd38c8d85.1614674882.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
Today we have: #ifdef __powerpc64__ #define user_mode(regs) ((((regs)->msr) >> MSR_PR_LG) & 0x1) #else #define user_mode(regs) (((regs)->msr & MSR_PR) != 0) #endif With ppc64_defconfig, we get: if (!user_mode(regs)) 14b4: e9 3e 01 08 ld r9,264(r30) 14b8: 71 29 40 00 andi. r9,r9,16384 14bc: 41 82 07 a4 beq 1c60 <.emulate_instruction+0x7d0> If taking the ppc32 definition of user_mode(), the exact same code is generated for ppc64_defconfig. So, only keep one version of user_mode(), preferably the one not using MSR_PR_LG which should be kept internal to reg.h. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/000a28c51808bbd802b505af42d2cb316c2be7d3.1629216000.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
When shift is nul, operations remain valid so no test needed. And 'ret' is unnecessary. And use IS_ALIGNED() to check alignment, that's more clear. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/373ec500f386374bc5735007df3d3869eac47be1.1624618701.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
This patch converts powerpc to the generic PTDUMP implementation. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/03166d569526be70214fe9370a7bad219d2f41c8.1625762907.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
Do the same as commit f8f0d0b6 ("mm: ptdump: reduce level numbers by 1 in note_page()") and add missing p4d level. This will align powerpc to the users of generic ptdump. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/d76495c574132b197b445a1f133755cca4b912a4.1625762906.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
note_page_update_state() doesn't use page_size. Remove it. Could also be removed to note_page() but as a following patch will remove all current users of note_page(), just leave it as is for now. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/e2f80d052001155251bfe009c360d0c5d9242c6b.1625762906.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
Use DEFINE_SHOW_ATTRIBUTE() instead of open coding open() and fops. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/b864a92693ca8413ef0b19f0c12065c212899b6e.1625762905.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
bl;mflr is used at several places to get code position. Use bcl 20,31,+4 instead of bl in order to preserve link stack. See commit c974809a ("powerpc/vdso: Avoid link stack corruption in __get_datapage()") for details. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/c6eabb4fb6c156f75d56dcbcc6f243e5ac0fba42.1629791763.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
Use bcl 20,31,+4 instead of bl in order to preserve link stack. See commit c974809a ("powerpc/vdso: Avoid link stack corruption in __get_datapage()") for details. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/e9fbc285eceb720e6c0e032ef47fe8b05f669b48.1629791751.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
Copied from commit 89bbe4c7 ("powerpc/64: indirect function call use bctrl rather than blrl in ret_from_kernel_thread") blrl is not recommended to use as an indirect function call, as it may corrupt the link stack predictor. This is not a performance critical path but this should be fixed for consistency. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/91b1d242525307ceceec7ef6e832bfbacdd4501b.1629436472.git.christophe.leroy@csgroup.eu
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- 24 Aug, 2021 3 commits
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Fabiano Rosas authored
The book3s_64_mmu_radix.o object is not part of the KVM builtins and all the callers of the exported symbols are in the same kvm-hv.ko module so we should not need to export any symbols. Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210805212616.2641017-4-farosas@linux.ibm.com
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Fabiano Rosas authored
Both paths into __kvmhv_copy_tofrom_guest_radix ensure that we arrive with an effective address that is smaller than our total addressable space and addresses quadrant 0. - The H_COPY_TOFROM_GUEST hypercall path rejects the call with H_PARAMETER if the effective address has any of the twelve most significant bits set. - The kvmhv_copy_tofrom_guest_radix path clears the top twelve bits before calling the internal function. Although the callers make sure that the effective address is sane, any future use of the function is exposed to a programming error, so add a sanity check. Suggested-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210805212616.2641017-3-farosas@linux.ibm.com
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Fabiano Rosas authored
The __kvmhv_copy_tofrom_guest_radix function was introduced along with nested HV guest support. It uses the platform's Radix MMU quadrants to provide a nested hypervisor with fast access to its nested guests memory (H_COPY_TOFROM_GUEST hypercall). It has also since been added as a fast path for the kvmppc_ld/st routines which are used during instruction emulation. The commit def0bfdb ("powerpc: use probe_user_read() and probe_user_write()") changed the low level copy function from raw_copy_from_user to probe_user_read, which adds a check to access_ok. In powerpc that is: static inline bool __access_ok(unsigned long addr, unsigned long size) { return addr < TASK_SIZE_MAX && size <= TASK_SIZE_MAX - addr; } and TASK_SIZE_MAX is 0x0010000000000000UL for 64-bit, which means that setting the two MSBs of the effective address (which correspond to the quadrant) now cause access_ok to reject the access. This was not caught earlier because the most common code path via kvmppc_ld/st contains a fallback (kvm_read_guest) that is likely to succeed for L1 guests. For nested guests there is no fallback. Another issue is that probe_user_read (now __copy_from_user_nofault) does not return the number of bytes not copied in case of failure, so the destination memory is not being cleared anymore in kvmhv_copy_from_guest_radix: ret = kvmhv_copy_tofrom_guest_radix(vcpu, eaddr, to, NULL, n); if (ret > 0) <-- always false! memset(to + (n - ret), 0, ret); This patch fixes both issues by skipping access_ok and open-coding the low level __copy_to/from_user_inatomic. Fixes: def0bfdb ("powerpc: use probe_user_read() and probe_user_write()") Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210805212616.2641017-2-farosas@linux.ibm.com
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