BMC/Intel-BMC/linux.git/arch/powerpc/kvm, branch v5.2.7

KVM: PPC: Book3S HV: XIVE: fix rollback when kvmppc_xive_create fails

2019-07-31T05:24:57+00:00

commit 9798f4ea71eaf8eaad7e688c5b298528089c7bf8 upstream. The XIVE device structure is now allocated in kvmppc_xive_get_device() and kfree'd in kvmppc_core_destroy_vm(). In case of an OPAL error when allocating the XIVE VPs, the kfree() call in kvmppc_xive_*create() will result in a double free and corrupt the host memory. Fixes: 5422e95103cf ("KVM: PPC: Book3S HV: XIVE: Replace the 'destroy' method by a 'release' method") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Cédric Le Goater Tested-by: Michael Ellerman Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/6ea6998b-a890-2511-01d1-747d7621eb19@kaod.org Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Save and restore guest visible PSSCR bits on pseries

2019-07-31T05:24:57+00:00

commit c8b4083db915dfe5a3b4a755ad2317e0509b43f1 upstream. The Performance Stop Status and Control Register (PSSCR) is used to control the power saving facilities of the processor. This register has various fields, some of which can be modified only in hypervisor state, and others which can be modified in both hypervisor and privileged non-hypervisor state. The bits which can be modified in privileged non-hypervisor state are referred to as guest visible. Currently the L0 hypervisor saves and restores both it's own host value as well as the guest value of the PSSCR when context switching between the hypervisor and guest. However a nested hypervisor running it's own nested guests (as indicated by kvmhv_on_pseries()) doesn't context switch the PSSCR register. That means if a nested (L2) guest modifies the PSSCR then the L1 guest hypervisor will run with that modified value, and if the L1 guest hypervisor modifies the PSSCR and then goes to run the nested (L2) guest again then the L2 PSSCR value will be lost. Fix this by having the (L1) nested hypervisor save and restore both its host and the guest PSSCR value when entering and exiting a nested (L2) guest. Note that only the guest visible parts of the PSSCR are context switched since this is all the L1 nested hypervisor can access, this is fine however as these are the only fields the L0 hypervisor provides guest control of anyway and so all other fields are ignored. This could also have been implemented by adding the PSSCR register to the hv_regs passed to the L0 hypervisor as input to the H_ENTER_NESTED hcall, however this would have meant updating the structure layout and thus required modifications to both the L0 and L1 kernels. Whereas the approach used doesn't require L0 kernel modifications while achieving the same result. Fixes: 95a6432ce903 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Suraj Jitindar Singh Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190703012022.15644-3-sjitindarsingh@gmail.com Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Always save guest pmu for guest capable of nesting

2019-07-31T05:24:57+00:00

commit 63279eeb7f93abb1692573c26f1e038e1a87358b upstream. The performance monitoring unit (PMU) registers are saved on guest exit when the guest has set the pmcregs_in_use flag in its lppaca, if it exists, or unconditionally if it doesn't. If a nested guest is being run then the hypervisor doesn't, and in most cases can't, know if the PMU registers are in use since it doesn't know the location of the lppaca for the nested guest, although it may have one for its immediate guest. This results in the values of these registers being lost across nested guest entry and exit in the case where the nested guest was making use of the performance monitoring facility while it's nested guest hypervisor wasn't. Further more the hypervisor could interrupt a guest hypervisor between when it has loaded up the PMU registers and it calling H_ENTER_NESTED or between returning from the nested guest to the guest hypervisor and the guest hypervisor reading the PMU registers, in kvmhv_p9_guest_entry(). This means that it isn't sufficient to just save the PMU registers when entering or exiting a nested guest, but that it is necessary to always save the PMU registers whenever a guest is capable of running nested guests to ensure the register values aren't lost in the context switch. Ensure the PMU register values are preserved by always saving their value into the vcpu struct when a guest is capable of running nested guests. This should have minimal performance impact however any impact can be avoided by booting a guest with "-machine pseries,cap-nested-hv=false" on the qemu commandline. Fixes: 95a6432ce903 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Suraj Jitindar Singh Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190703012022.15644-1-sjitindarsingh@gmail.com Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Fix CR0 setting in TM emulation

2019-07-26T07:11:00+00:00

commit 3fefd1cd95df04da67c83c1cb93b663f04b3324f upstream. When emulating tsr, treclaim and trechkpt, we incorrectly set CR0. The code currently sets: CR0 <- 00 || MSR[TS] but according to the ISA it should be: CR0 <- 0 || MSR[TS] || 0 This fixes the bit shift to put the bits in the correct location. This is a data integrity issue as CR0 is corrupted. Fixes: 4bb3c7a0208f ("KVM: PPC: Book3S HV: Work around transactional memory bugs in POWER9") Cc: stable@vger.kernel.org # v4.17+ Tested-by: Suraj Jitindar Singh Signed-off-by: Michael Neuling Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Clear pending decrementer exceptions on nested guest entry

2019-07-26T07:11:00+00:00

commit 3c25ab35fbc8526ac0c9b298e8a78e7ad7a55479 upstream. If we enter an L1 guest with a pending decrementer exception then this is cleared on guest exit if the guest has writtien a positive value into the decrementer (indicating that it handled the decrementer exception) since there is no other way to detect that the guest has handled the pending exception and that it should be dequeued. In the event that the L1 guest tries to run a nested (L2) guest immediately after this and the L2 guest decrementer is negative (which is loaded by L1 before making the H_ENTER_NESTED hcall), then the pending decrementer exception isn't cleared and the L2 entry is blocked since L1 has a pending exception, even though L1 may have already handled the exception and written a positive value for it's decrementer. This results in a loop of L1 trying to enter the L2 guest and L0 blocking the entry since L1 has an interrupt pending with the outcome being that L2 never gets to run and hangs. Fix this by clearing any pending decrementer exceptions when L1 makes the H_ENTER_NESTED hcall since it won't do this if it's decrementer has gone negative, and anyway it's decrementer has been communicated to L0 in the hdec_expires field and L0 will return control to L1 when this goes negative by delivering an H_DECREMENTER exception. Fixes: 95a6432ce903 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Suraj Jitindar Singh Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Signed extend decrementer value if not using large decrementer

2019-07-26T07:11:00+00:00

commit 869537709ebf1dc865e75c3fc97b23f8acf37c16 upstream. On POWER9 the decrementer can operate in large decrementer mode where the decrementer is 56 bits and signed extended to 64 bits. When not operating in this mode the decrementer behaves as a 32 bit decrementer which is NOT signed extended (as on POWER8). Currently when reading a guest decrementer value we don't take into account whether the large decrementer is enabled or not, and this means the value will be incorrect when the guest is not using the large decrementer. Fix this by sign extending the value read when the guest isn't using the large decrementer. Fixes: 95a6432ce903 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Suraj Jitindar Singh Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

Merge tag 'powerpc-5.2-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2019-06-22T16:09:42+00:00

Pull powerpc fixes from Michael Ellerman: "This is a frustratingly large batch at rc5. Some of these were sent earlier but were missed by me due to being distracted by other things, and some took a while to track down due to needing manual bisection on old hardware. But still we clearly need to improve our testing of KVM, and of 32-bit, so that we catch these earlier. Summary: seven fixes, all for bugs introduced this cycle. - The commit to add KASAN support broke booting on 32-bit SMP machines, due to a refactoring that moved some setup out of the secondary CPU path. - A fix for another 32-bit SMP bug introduced by the fast syscall entry implementation for 32-bit BOOKE. And a build fix for the same commit. - Our change to allow the DAWR to be force enabled on Power9 introduced a bug in KVM, where we clobber r3 leading to a host crash. - The same commit also exposed a previously unreachable bug in the nested KVM handling of DAWR, which could lead to an oops in a nested host. - One of the DMA reworks broke the b43legacy WiFi driver on some people's powermacs, fix it by enabling a 30-bit ZONE_DMA on 32-bit. - A fix for TLB flushing in KVM introduced a new bug, as it neglected to also flush the ERAT, this could lead to memory corruption in the guest. Thanks to: Aaro Koskinen, Christoph Hellwig, Christophe Leroy, Larry Finger, Michael Neuling, Suraj Jitindar Singh" * tag 'powerpc-5.2-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: KVM: PPC: Book3S HV: Invalidate ERAT when flushing guest TLB entries powerpc: enable a 30-bit ZONE_DMA for 32-bit pmac KVM: PPC: Book3S HV: Only write DAWR[X] when handling h_set_dawr in real mode KVM: PPC: Book3S HV: Fix r3 corruption in h_set_dabr() powerpc/32: fix build failure on book3e with KVM powerpc/booke: fix fast syscall entry on SMP powerpc/32s: fix initial setup of segment registers on secondary CPU

KVM: PPC: Book3S HV: Invalidate ERAT when flushing guest TLB entries

2019-06-20T12:11:25+00:00

When a guest vcpu moves from one physical thread to another it is necessary for the host to perform a tlb flush on the previous core if another vcpu from the same guest is going to run there. This is because the guest may use the local form of the tlb invalidation instruction meaning stale tlb entries would persist where it previously ran. This is handled on guest entry in kvmppc_check_need_tlb_flush() which calls flush_guest_tlb() to perform the tlb flush. Previously the generic radix__local_flush_tlb_lpid_guest() function was used, however the functionality was reimplemented in flush_guest_tlb() to avoid the trace_tlbie() call as the flushing may be done in real mode. The reimplementation in flush_guest_tlb() was missing an erat invalidation after flushing the tlb. This lead to observable memory corruption in the guest due to the caching of stale translations. Fix this by adding the erat invalidation. Fixes: 70ea13f6e609 ("KVM: PPC: Book3S HV: Flush TLB on secondary radix threads") Signed-off-by: Suraj Jitindar Singh Signed-off-by: Michael Ellerman

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Only write DAWR[X] when handling h_set_dawr in real mode

2019-06-18T00:21:19+00:00

The hcall H_SET_DAWR is used by a guest to set the data address watchpoint register (DAWR). This hcall is handled in the host in kvmppc_h_set_dawr() which can be called in either real mode on the guest exit path from hcall_try_real_mode() in book3s_hv_rmhandlers.S, or in virtual mode when called from kvmppc_pseries_do_hcall() in book3s_hv.c. The function kvmppc_h_set_dawr() updates the dawr and dawrx fields in the vcpu struct accordingly and then also writes the respective values into the DAWR and DAWRX registers directly. It is necessary to write the registers directly here when calling the function in real mode since the path to re-enter the guest won't do this. However when in virtual mode the host DAWR and DAWRX values have already been restored, and so writing the registers would overwrite these. Additionally there is no reason to write the guest values here as these will be read from the vcpu struct and written to the registers appropriately the next time the vcpu is run. This also avoids the case when handling h_set_dawr for a nested guest where the guest hypervisor isn't able to write the DAWR and DAWRX registers directly and must rely on the real hypervisor to do this for it when it calls H_ENTER_NESTED. Fixes: c1fe190c0672 ("powerpc: Add force enable of DAWR on P9 option") Signed-off-by: Suraj Jitindar Singh Signed-off-by: Michael Ellerman