* [PATCH AUTOSEL 5.9 002/147] powerpc/powernv/smp: Fix spurious DBG() warning
From: Sasha Levin @ 2020-10-26 23:46 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, linuxppc-dev, Oliver O'Halloran, Joel Stanley
In-Reply-To: <20201026234905.1022767-1-sashal@kernel.org>
From: Oliver O'Halloran <oohall@gmail.com>
[ Upstream commit f6bac19cf65c5be21d14a0c9684c8f560f2096dd ]
When building with W=1 we get the following warning:
arch/powerpc/platforms/powernv/smp.c: In function ‘pnv_smp_cpu_kill_self’:
arch/powerpc/platforms/powernv/smp.c:276:16: error: suggest braces around
empty body in an ‘if’ statement [-Werror=empty-body]
276 | cpu, srr1);
| ^
cc1: all warnings being treated as errors
The full context is this block:
if (srr1 && !generic_check_cpu_restart(cpu))
DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
cpu, srr1);
When building with DEBUG undefined DBG() expands to nothing and GCC emits
the warning due to the lack of braces around an empty statement.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-2-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/powernv/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index b2ba3e95bda73..bbf361f23ae86 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -43,7 +43,7 @@
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
-#define DBG(fmt...)
+#define DBG(fmt...) do { } while (0)
#endif
static void pnv_smp_setup_cpu(int cpu)
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.9 005/147] powerpc/watchpoint/ptrace: Fix SETHWDEBUG when CONFIG_HAVE_HW_BREAKPOINT=N
From: Sasha Levin @ 2020-10-26 23:46 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, Ravi Bangoria, Pedro Miraglia Franco de Carvalho,
linuxppc-dev
In-Reply-To: <20201026234905.1022767-1-sashal@kernel.org>
From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
[ Upstream commit 9b6b7c680cc20971444d9f836e49fc98848bcd0a ]
When kernel is compiled with CONFIG_HAVE_HW_BREAKPOINT=N, user can
still create watchpoint using PPC_PTRACE_SETHWDEBUG, with limited
functionalities. But, such watchpoints are never firing because of
the missing privilege settings. Fix that.
It's safe to set HW_BRK_TYPE_PRIV_ALL because we don't really leak
any kernel address in signal info. Setting HW_BRK_TYPE_PRIV_ALL will
also help to find scenarios when kernel accesses user memory.
Reported-by: Pedro Miraglia Franco de Carvalho <pedromfc@linux.ibm.com>
Suggested-by: Pedro Miraglia Franco de Carvalho <pedromfc@linux.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200902042945.129369-4-ravi.bangoria@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kernel/ptrace/ptrace-noadv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/ptrace/ptrace-noadv.c b/arch/powerpc/kernel/ptrace/ptrace-noadv.c
index 697c7e4b5877f..57a0ab822334f 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-noadv.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-noadv.c
@@ -217,7 +217,7 @@ long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_inf
return -EIO;
brk.address = ALIGN_DOWN(bp_info->addr, HW_BREAKPOINT_SIZE);
- brk.type = HW_BRK_TYPE_TRANSLATE;
+ brk.type = HW_BRK_TYPE_TRANSLATE | HW_BRK_TYPE_PRIV_ALL;
brk.len = DABR_MAX_LEN;
if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
brk.type |= HW_BRK_TYPE_READ;
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.9 007/147] powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
From: Sasha Levin @ 2020-10-26 23:46 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev, Nicholas Piggin
In-Reply-To: <20201026234905.1022767-1-sashal@kernel.org>
From: Nicholas Piggin <npiggin@gmail.com>
[ Upstream commit 66acd46080bd9e5ad2be4b0eb1d498d5145d058e ]
powerpc uses IPIs in some situations to switch a kernel thread away
from a lazy tlb mm, which is subject to the TLB flushing race
described in the changelog introducing ARCH_WANT_IRQS_OFF_ACTIVATE_MM.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-3-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/mmu_context.h | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 787e829b6f25c..8250c0fd85285 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -148,6 +148,7 @@ config PPC
select ARCH_USE_QUEUED_RWLOCKS if PPC_QUEUED_SPINLOCKS
select ARCH_USE_QUEUED_SPINLOCKS if PPC_QUEUED_SPINLOCKS
select ARCH_WANT_IPC_PARSE_VERSION
+ select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
select ARCH_WEAK_RELEASE_ACQUIRE
select BINFMT_ELF
select BUILDTIME_TABLE_SORT
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 7f3658a973846..e02aa793420b8 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -244,7 +244,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
*/
static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
- switch_mm(prev, next, current);
+ switch_mm_irqs_off(prev, next, current);
}
/* We don't currently use enter_lazy_tlb() for anything */
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.9 020/147] powerpc/64s: handle ISA v3.1 local copy-paste context switches
From: Sasha Levin @ 2020-10-26 23:46 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Sasha Levin, kvm-ppc, Nicholas Piggin, linuxppc-dev
In-Reply-To: <20201026234905.1022767-1-sashal@kernel.org>
From: Nicholas Piggin <npiggin@gmail.com>
[ Upstream commit dc462267d2d7aacffc3c1d99b02d7a7c59db7c66 ]
The ISA v3.1 the copy-paste facility has a new memory move functionality
which allows the copy buffer to be pasted to domestic memory (RAM) as
opposed to foreign memory (accelerator).
This means the POWER9 trick of avoiding the cp_abort on context switch if
the process had not mapped foreign memory does not work on POWER10. Do the
cp_abort unconditionally there.
KVM must also cp_abort on guest exit to prevent copy buffer state leaking
between contexts.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200825075535.224536-1-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kernel/process.c | 16 +++++++++-------
arch/powerpc/kvm/book3s_hv.c | 7 +++++++
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 8 ++++++++
3 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 73a57043ee662..3f2dc0675ea7a 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1256,15 +1256,17 @@ struct task_struct *__switch_to(struct task_struct *prev,
restore_math(current->thread.regs);
/*
- * The copy-paste buffer can only store into foreign real
- * addresses, so unprivileged processes can not see the
- * data or use it in any way unless they have foreign real
- * mappings. If the new process has the foreign real address
- * mappings, we must issue a cp_abort to clear any state and
- * prevent snooping, corruption or a covert channel.
+ * On POWER9 the copy-paste buffer can only paste into
+ * foreign real addresses, so unprivileged processes can not
+ * see the data or use it in any way unless they have
+ * foreign real mappings. If the new process has the foreign
+ * real address mappings, we must issue a cp_abort to clear
+ * any state and prevent snooping, corruption or a covert
+ * channel. ISA v3.1 supports paste into local memory.
*/
if (current->mm &&
- atomic_read(¤t->mm->context.vas_windows))
+ (cpu_has_feature(CPU_FTR_ARCH_31) ||
+ atomic_read(¤t->mm->context.vas_windows)))
asm volatile(PPC_CP_ABORT);
}
#endif /* CONFIG_PPC_BOOK3S_64 */
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 4ba06a2a306cf..3bd3118c76330 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3530,6 +3530,13 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
*/
asm volatile("eieio; tlbsync; ptesync");
+ /*
+ * cp_abort is required if the processor supports local copy-paste
+ * to clear the copy buffer that was under control of the guest.
+ */
+ if (cpu_has_feature(CPU_FTR_ARCH_31))
+ asm volatile(PPC_CP_ABORT);
+
mtspr(SPRN_LPID, vcpu->kvm->arch.host_lpid); /* restore host LPID */
isync();
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 799d6d0f4eade..cd9995ee84419 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1830,6 +1830,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_RADIX_PREFETCH_BUG)
2:
#endif /* CONFIG_PPC_RADIX_MMU */
+ /*
+ * cp_abort is required if the processor supports local copy-paste
+ * to clear the copy buffer that was under control of the guest.
+ */
+BEGIN_FTR_SECTION
+ PPC_CP_ABORT
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_31)
+
/*
* POWER7/POWER8 guest -> host partition switch code.
* We don't have to lock against tlbies but we do
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.9 058/147] selftests/powerpc: Make using_hash_mmu() work on Cell & PowerMac
From: Sasha Levin @ 2020-10-26 23:47 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev, linux-kselftest
In-Reply-To: <20201026234905.1022767-1-sashal@kernel.org>
From: Michael Ellerman <mpe@ellerman.id.au>
[ Upstream commit 34c103342be3f9397e656da7c5cc86e97b91f514 ]
These platforms don't show the MMU in /proc/cpuinfo, but they always
use hash, so teach using_hash_mmu() that.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200819015727.1977134-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/testing/selftests/powerpc/utils.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/powerpc/utils.c b/tools/testing/selftests/powerpc/utils.c
index 18b6a773d5c73..638ffacc90aa1 100644
--- a/tools/testing/selftests/powerpc/utils.c
+++ b/tools/testing/selftests/powerpc/utils.c
@@ -318,7 +318,9 @@ int using_hash_mmu(bool *using_hash)
rc = 0;
while (fgets(line, sizeof(line), f) != NULL) {
- if (strcmp(line, "MMU : Hash\n") == 0) {
+ if (!strcmp(line, "MMU : Hash\n") ||
+ !strcmp(line, "platform : Cell\n") ||
+ !strcmp(line, "platform : PowerMac\n")) {
*using_hash = true;
goto out;
}
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.9 121/147] KVM: PPC: Book3S HV: Do not allocate HPT for a nested guest
From: Sasha Levin @ 2020-10-26 23:48 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, Fabiano Rosas, Greg Kurz, kvm-ppc,
Satheesh Rajendran, linuxppc-dev, David Gibson
In-Reply-To: <20201026234905.1022767-1-sashal@kernel.org>
From: Fabiano Rosas <farosas@linux.ibm.com>
[ Upstream commit 05e6295dc7de859c9d56334805485c4d20bebf25 ]
The current nested KVM code does not support HPT guests. This is
informed/enforced in some ways:
- Hosts < P9 will not be able to enable the nested HV feature;
- The nested hypervisor MMU capabilities will not contain
KVM_CAP_PPC_MMU_HASH_V3;
- QEMU reflects the MMU capabilities in the
'ibm,arch-vec-5-platform-support' device-tree property;
- The nested guest, at 'prom_parse_mmu_model' ignores the
'disable_radix' kernel command line option if HPT is not supported;
- The KVM_PPC_CONFIGURE_V3_MMU ioctl will fail if trying to use HPT.
There is, however, still a way to start a HPT guest by using
max-compat-cpu=power8 at the QEMU machine options. This leads to the
guest being set to use hash after QEMU calls the KVM_PPC_ALLOCATE_HTAB
ioctl.
With the guest set to hash, the nested hypervisor goes through the
entry path that has no knowledge of nesting (kvmppc_run_vcpu) and
crashes when it tries to execute an hypervisor-privileged (mtspr
HDEC) instruction at __kvmppc_vcore_entry:
root@L1:~ $ qemu-system-ppc64 -machine pseries,max-cpu-compat=power8 ...
<snip>
[ 538.543303] CPU: 83 PID: 25185 Comm: CPU 0/KVM Not tainted 5.9.0-rc4 #1
[ 538.543355] NIP: c00800000753f388 LR: c00800000753f368 CTR: c0000000001e5ec0
[ 538.543417] REGS: c0000013e91e33b0 TRAP: 0700 Not tainted (5.9.0-rc4)
[ 538.543470] MSR: 8000000002843033 <SF,VEC,VSX,FP,ME,IR,DR,RI,LE> CR: 22422882 XER: 20040000
[ 538.543546] CFAR: c00800000753f4b0 IRQMASK: 3
GPR00: c0080000075397a0 c0000013e91e3640 c00800000755e600 0000000080000000
GPR04: 0000000000000000 c0000013eab19800 c000001394de0000 00000043a054db72
GPR08: 00000000003b1652 0000000000000000 0000000000000000 c0080000075502e0
GPR12: c0000000001e5ec0 c0000007ffa74200 c0000013eab19800 0000000000000008
GPR16: 0000000000000000 c00000139676c6c0 c000000001d23948 c0000013e91e38b8
GPR20: 0000000000000053 0000000000000000 0000000000000001 0000000000000000
GPR24: 0000000000000001 0000000000000001 0000000000000000 0000000000000001
GPR28: 0000000000000001 0000000000000053 c0000013eab19800 0000000000000001
[ 538.544067] NIP [c00800000753f388] __kvmppc_vcore_entry+0x90/0x104 [kvm_hv]
[ 538.544121] LR [c00800000753f368] __kvmppc_vcore_entry+0x70/0x104 [kvm_hv]
[ 538.544173] Call Trace:
[ 538.544196] [c0000013e91e3640] [c0000013e91e3680] 0xc0000013e91e3680 (unreliable)
[ 538.544260] [c0000013e91e3820] [c0080000075397a0] kvmppc_run_core+0xbc8/0x19d0 [kvm_hv]
[ 538.544325] [c0000013e91e39e0] [c00800000753d99c] kvmppc_vcpu_run_hv+0x404/0xc00 [kvm_hv]
[ 538.544394] [c0000013e91e3ad0] [c0080000072da4fc] kvmppc_vcpu_run+0x34/0x48 [kvm]
[ 538.544472] [c0000013e91e3af0] [c0080000072d61b8] kvm_arch_vcpu_ioctl_run+0x310/0x420 [kvm]
[ 538.544539] [c0000013e91e3b80] [c0080000072c7450] kvm_vcpu_ioctl+0x298/0x778 [kvm]
[ 538.544605] [c0000013e91e3ce0] [c0000000004b8c2c] sys_ioctl+0x1dc/0xc90
[ 538.544662] [c0000013e91e3dc0] [c00000000002f9a4] system_call_exception+0xe4/0x1c0
[ 538.544726] [c0000013e91e3e20] [c00000000000d140] system_call_common+0xf0/0x27c
[ 538.544787] Instruction dump:
[ 538.544821] f86d1098 60000000 60000000 48000099 e8ad0fe8 e8c500a0 e9264140 75290002
[ 538.544886] 7d1602a6 7cec42a6 40820008 7d0807b4 <7d164ba6> 7d083a14 f90d10a0 480104fd
[ 538.544953] ---[ end trace 74423e2b948c2e0c ]---
This patch makes the KVM_PPC_ALLOCATE_HTAB ioctl fail when running in
the nested hypervisor, causing QEMU to abort.
Reported-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kvm/book3s_hv.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 3bd3118c76330..e2b476d76506a 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -5257,6 +5257,12 @@ static long kvm_arch_vm_ioctl_hv(struct file *filp,
case KVM_PPC_ALLOCATE_HTAB: {
u32 htab_order;
+ /* If we're a nested hypervisor, we currently only support radix */
+ if (kvmhv_on_pseries()) {
+ r = -EOPNOTSUPP;
+ break;
+ }
+
r = -EFAULT;
if (get_user(htab_order, (u32 __user *)argp))
break;
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.8 001/132] powerpc/powernv/smp: Fix spurious DBG() warning
From: Sasha Levin @ 2020-10-26 23:49 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, linuxppc-dev, Oliver O'Halloran, Joel Stanley
From: Oliver O'Halloran <oohall@gmail.com>
[ Upstream commit f6bac19cf65c5be21d14a0c9684c8f560f2096dd ]
When building with W=1 we get the following warning:
arch/powerpc/platforms/powernv/smp.c: In function ‘pnv_smp_cpu_kill_self’:
arch/powerpc/platforms/powernv/smp.c:276:16: error: suggest braces around
empty body in an ‘if’ statement [-Werror=empty-body]
276 | cpu, srr1);
| ^
cc1: all warnings being treated as errors
The full context is this block:
if (srr1 && !generic_check_cpu_restart(cpu))
DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
cpu, srr1);
When building with DEBUG undefined DBG() expands to nothing and GCC emits
the warning due to the lack of braces around an empty statement.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-2-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/powernv/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index b2ba3e95bda73..bbf361f23ae86 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -43,7 +43,7 @@
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
-#define DBG(fmt...)
+#define DBG(fmt...) do { } while (0)
#endif
static void pnv_smp_setup_cpu(int cpu)
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.8 004/132] powerpc/watchpoint/ptrace: Fix SETHWDEBUG when CONFIG_HAVE_HW_BREAKPOINT=N
From: Sasha Levin @ 2020-10-26 23:49 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, Ravi Bangoria, Pedro Miraglia Franco de Carvalho,
linuxppc-dev
In-Reply-To: <20201026235205.1023962-1-sashal@kernel.org>
From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
[ Upstream commit 9b6b7c680cc20971444d9f836e49fc98848bcd0a ]
When kernel is compiled with CONFIG_HAVE_HW_BREAKPOINT=N, user can
still create watchpoint using PPC_PTRACE_SETHWDEBUG, with limited
functionalities. But, such watchpoints are never firing because of
the missing privilege settings. Fix that.
It's safe to set HW_BRK_TYPE_PRIV_ALL because we don't really leak
any kernel address in signal info. Setting HW_BRK_TYPE_PRIV_ALL will
also help to find scenarios when kernel accesses user memory.
Reported-by: Pedro Miraglia Franco de Carvalho <pedromfc@linux.ibm.com>
Suggested-by: Pedro Miraglia Franco de Carvalho <pedromfc@linux.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200902042945.129369-4-ravi.bangoria@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kernel/ptrace/ptrace-noadv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/ptrace/ptrace-noadv.c b/arch/powerpc/kernel/ptrace/ptrace-noadv.c
index 697c7e4b5877f..57a0ab822334f 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-noadv.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-noadv.c
@@ -217,7 +217,7 @@ long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_inf
return -EIO;
brk.address = ALIGN_DOWN(bp_info->addr, HW_BREAKPOINT_SIZE);
- brk.type = HW_BRK_TYPE_TRANSLATE;
+ brk.type = HW_BRK_TYPE_TRANSLATE | HW_BRK_TYPE_PRIV_ALL;
brk.len = DABR_MAX_LEN;
if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
brk.type |= HW_BRK_TYPE_READ;
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.8 006/132] powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
From: Sasha Levin @ 2020-10-26 23:49 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev, Nicholas Piggin
In-Reply-To: <20201026235205.1023962-1-sashal@kernel.org>
From: Nicholas Piggin <npiggin@gmail.com>
[ Upstream commit 66acd46080bd9e5ad2be4b0eb1d498d5145d058e ]
powerpc uses IPIs in some situations to switch a kernel thread away
from a lazy tlb mm, which is subject to the TLB flushing race
described in the changelog introducing ARCH_WANT_IRQS_OFF_ACTIVATE_MM.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-3-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/mmu_context.h | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9fa23eb320ff5..1692c9def44c9 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -146,6 +146,7 @@ config PPC
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF if PPC64
select ARCH_WANT_IPC_PARSE_VERSION
+ select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
select ARCH_WEAK_RELEASE_ACQUIRE
select BINFMT_ELF
select BUILDTIME_TABLE_SORT
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 1a474f6b1992a..6cb10c7a52025 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -246,7 +246,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
*/
static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
- switch_mm(prev, next, current);
+ switch_mm_irqs_off(prev, next, current);
}
/* We don't currently use enter_lazy_tlb() for anything */
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.8 018/132] powerpc/64s: handle ISA v3.1 local copy-paste context switches
From: Sasha Levin @ 2020-10-26 23:50 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Sasha Levin, kvm-ppc, Nicholas Piggin, linuxppc-dev
In-Reply-To: <20201026235205.1023962-1-sashal@kernel.org>
From: Nicholas Piggin <npiggin@gmail.com>
[ Upstream commit dc462267d2d7aacffc3c1d99b02d7a7c59db7c66 ]
The ISA v3.1 the copy-paste facility has a new memory move functionality
which allows the copy buffer to be pasted to domestic memory (RAM) as
opposed to foreign memory (accelerator).
This means the POWER9 trick of avoiding the cp_abort on context switch if
the process had not mapped foreign memory does not work on POWER10. Do the
cp_abort unconditionally there.
KVM must also cp_abort on guest exit to prevent copy buffer state leaking
between contexts.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200825075535.224536-1-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kernel/process.c | 16 +++++++++-------
arch/powerpc/kvm/book3s_hv.c | 7 +++++++
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 8 ++++++++
3 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 4650b9bb217fb..fcae69ac9acaa 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1231,15 +1231,17 @@ struct task_struct *__switch_to(struct task_struct *prev,
restore_math(current->thread.regs);
/*
- * The copy-paste buffer can only store into foreign real
- * addresses, so unprivileged processes can not see the
- * data or use it in any way unless they have foreign real
- * mappings. If the new process has the foreign real address
- * mappings, we must issue a cp_abort to clear any state and
- * prevent snooping, corruption or a covert channel.
+ * On POWER9 the copy-paste buffer can only paste into
+ * foreign real addresses, so unprivileged processes can not
+ * see the data or use it in any way unless they have
+ * foreign real mappings. If the new process has the foreign
+ * real address mappings, we must issue a cp_abort to clear
+ * any state and prevent snooping, corruption or a covert
+ * channel. ISA v3.1 supports paste into local memory.
*/
if (current->mm &&
- atomic_read(¤t->mm->context.vas_windows))
+ (cpu_has_feature(CPU_FTR_ARCH_31) ||
+ atomic_read(¤t->mm->context.vas_windows)))
asm volatile(PPC_CP_ABORT);
}
#endif /* CONFIG_PPC_BOOK3S_64 */
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6bf66649ab92f..1928b86d6e6b5 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3485,6 +3485,13 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
*/
asm volatile("eieio; tlbsync; ptesync");
+ /*
+ * cp_abort is required if the processor supports local copy-paste
+ * to clear the copy buffer that was under control of the guest.
+ */
+ if (cpu_has_feature(CPU_FTR_ARCH_31))
+ asm volatile(PPC_CP_ABORT);
+
mtspr(SPRN_LPID, vcpu->kvm->arch.host_lpid); /* restore host LPID */
isync();
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 71943892c81c6..092ef0ee29753 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1830,6 +1830,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_RADIX_PREFETCH_BUG)
2:
#endif /* CONFIG_PPC_RADIX_MMU */
+ /*
+ * cp_abort is required if the processor supports local copy-paste
+ * to clear the copy buffer that was under control of the guest.
+ */
+BEGIN_FTR_SECTION
+ PPC_CP_ABORT
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_31)
+
/*
* POWER7/POWER8 guest -> host partition switch code.
* We don't have to lock against tlbies but we do
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.8 112/132] KVM: PPC: Book3S HV: Do not allocate HPT for a nested guest
From: Sasha Levin @ 2020-10-26 23:51 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, Fabiano Rosas, Greg Kurz, kvm-ppc,
Satheesh Rajendran, linuxppc-dev, David Gibson
In-Reply-To: <20201026235205.1023962-1-sashal@kernel.org>
From: Fabiano Rosas <farosas@linux.ibm.com>
[ Upstream commit 05e6295dc7de859c9d56334805485c4d20bebf25 ]
The current nested KVM code does not support HPT guests. This is
informed/enforced in some ways:
- Hosts < P9 will not be able to enable the nested HV feature;
- The nested hypervisor MMU capabilities will not contain
KVM_CAP_PPC_MMU_HASH_V3;
- QEMU reflects the MMU capabilities in the
'ibm,arch-vec-5-platform-support' device-tree property;
- The nested guest, at 'prom_parse_mmu_model' ignores the
'disable_radix' kernel command line option if HPT is not supported;
- The KVM_PPC_CONFIGURE_V3_MMU ioctl will fail if trying to use HPT.
There is, however, still a way to start a HPT guest by using
max-compat-cpu=power8 at the QEMU machine options. This leads to the
guest being set to use hash after QEMU calls the KVM_PPC_ALLOCATE_HTAB
ioctl.
With the guest set to hash, the nested hypervisor goes through the
entry path that has no knowledge of nesting (kvmppc_run_vcpu) and
crashes when it tries to execute an hypervisor-privileged (mtspr
HDEC) instruction at __kvmppc_vcore_entry:
root@L1:~ $ qemu-system-ppc64 -machine pseries,max-cpu-compat=power8 ...
<snip>
[ 538.543303] CPU: 83 PID: 25185 Comm: CPU 0/KVM Not tainted 5.9.0-rc4 #1
[ 538.543355] NIP: c00800000753f388 LR: c00800000753f368 CTR: c0000000001e5ec0
[ 538.543417] REGS: c0000013e91e33b0 TRAP: 0700 Not tainted (5.9.0-rc4)
[ 538.543470] MSR: 8000000002843033 <SF,VEC,VSX,FP,ME,IR,DR,RI,LE> CR: 22422882 XER: 20040000
[ 538.543546] CFAR: c00800000753f4b0 IRQMASK: 3
GPR00: c0080000075397a0 c0000013e91e3640 c00800000755e600 0000000080000000
GPR04: 0000000000000000 c0000013eab19800 c000001394de0000 00000043a054db72
GPR08: 00000000003b1652 0000000000000000 0000000000000000 c0080000075502e0
GPR12: c0000000001e5ec0 c0000007ffa74200 c0000013eab19800 0000000000000008
GPR16: 0000000000000000 c00000139676c6c0 c000000001d23948 c0000013e91e38b8
GPR20: 0000000000000053 0000000000000000 0000000000000001 0000000000000000
GPR24: 0000000000000001 0000000000000001 0000000000000000 0000000000000001
GPR28: 0000000000000001 0000000000000053 c0000013eab19800 0000000000000001
[ 538.544067] NIP [c00800000753f388] __kvmppc_vcore_entry+0x90/0x104 [kvm_hv]
[ 538.544121] LR [c00800000753f368] __kvmppc_vcore_entry+0x70/0x104 [kvm_hv]
[ 538.544173] Call Trace:
[ 538.544196] [c0000013e91e3640] [c0000013e91e3680] 0xc0000013e91e3680 (unreliable)
[ 538.544260] [c0000013e91e3820] [c0080000075397a0] kvmppc_run_core+0xbc8/0x19d0 [kvm_hv]
[ 538.544325] [c0000013e91e39e0] [c00800000753d99c] kvmppc_vcpu_run_hv+0x404/0xc00 [kvm_hv]
[ 538.544394] [c0000013e91e3ad0] [c0080000072da4fc] kvmppc_vcpu_run+0x34/0x48 [kvm]
[ 538.544472] [c0000013e91e3af0] [c0080000072d61b8] kvm_arch_vcpu_ioctl_run+0x310/0x420 [kvm]
[ 538.544539] [c0000013e91e3b80] [c0080000072c7450] kvm_vcpu_ioctl+0x298/0x778 [kvm]
[ 538.544605] [c0000013e91e3ce0] [c0000000004b8c2c] sys_ioctl+0x1dc/0xc90
[ 538.544662] [c0000013e91e3dc0] [c00000000002f9a4] system_call_exception+0xe4/0x1c0
[ 538.544726] [c0000013e91e3e20] [c00000000000d140] system_call_common+0xf0/0x27c
[ 538.544787] Instruction dump:
[ 538.544821] f86d1098 60000000 60000000 48000099 e8ad0fe8 e8c500a0 e9264140 75290002
[ 538.544886] 7d1602a6 7cec42a6 40820008 7d0807b4 <7d164ba6> 7d083a14 f90d10a0 480104fd
[ 538.544953] ---[ end trace 74423e2b948c2e0c ]---
This patch makes the KVM_PPC_ALLOCATE_HTAB ioctl fail when running in
the nested hypervisor, causing QEMU to abort.
Reported-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kvm/book3s_hv.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 1928b86d6e6b5..51e8353310c2e 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -5214,6 +5214,12 @@ static long kvm_arch_vm_ioctl_hv(struct file *filp,
case KVM_PPC_ALLOCATE_HTAB: {
u32 htab_order;
+ /* If we're a nested hypervisor, we currently only support radix */
+ if (kvmhv_on_pseries()) {
+ r = -EOPNOTSUPP;
+ break;
+ }
+
r = -EFAULT;
if (get_user(htab_order, (u32 __user *)argp))
break;
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.4 01/80] powerpc/powernv/smp: Fix spurious DBG() warning
From: Sasha Levin @ 2020-10-26 23:53 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, linuxppc-dev, Oliver O'Halloran, Joel Stanley
From: Oliver O'Halloran <oohall@gmail.com>
[ Upstream commit f6bac19cf65c5be21d14a0c9684c8f560f2096dd ]
When building with W=1 we get the following warning:
arch/powerpc/platforms/powernv/smp.c: In function ‘pnv_smp_cpu_kill_self’:
arch/powerpc/platforms/powernv/smp.c:276:16: error: suggest braces around
empty body in an ‘if’ statement [-Werror=empty-body]
276 | cpu, srr1);
| ^
cc1: all warnings being treated as errors
The full context is this block:
if (srr1 && !generic_check_cpu_restart(cpu))
DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
cpu, srr1);
When building with DEBUG undefined DBG() expands to nothing and GCC emits
the warning due to the lack of braces around an empty statement.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-2-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/powernv/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index b2ba3e95bda73..bbf361f23ae86 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -43,7 +43,7 @@
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
-#define DBG(fmt...)
+#define DBG(fmt...) do { } while (0)
#endif
static void pnv_smp_setup_cpu(int cpu)
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.4 03/80] powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
From: Sasha Levin @ 2020-10-26 23:53 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev, Nicholas Piggin
In-Reply-To: <20201026235516.1025100-1-sashal@kernel.org>
From: Nicholas Piggin <npiggin@gmail.com>
[ Upstream commit 66acd46080bd9e5ad2be4b0eb1d498d5145d058e ]
powerpc uses IPIs in some situations to switch a kernel thread away
from a lazy tlb mm, which is subject to the TLB flushing race
described in the changelog introducing ARCH_WANT_IRQS_OFF_ACTIVATE_MM.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-3-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/mmu_context.h | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index ad620637cbd11..27ef333e96f6d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -147,6 +147,7 @@ config PPC
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF if PPC64
select ARCH_WANT_IPC_PARSE_VERSION
+ select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
select ARCH_WEAK_RELEASE_ACQUIRE
select BINFMT_ELF
select BUILDTIME_EXTABLE_SORT
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 58efca9343113..f132b418a8c7a 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -216,7 +216,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
*/
static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
- switch_mm(prev, next, current);
+ switch_mm_irqs_off(prev, next, current);
}
/* We don't currently use enter_lazy_tlb() for anything */
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 5.4 67/80] KVM: PPC: Book3S HV: Do not allocate HPT for a nested guest
From: Sasha Levin @ 2020-10-26 23:55 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, Fabiano Rosas, Greg Kurz, kvm-ppc,
Satheesh Rajendran, linuxppc-dev, David Gibson
In-Reply-To: <20201026235516.1025100-1-sashal@kernel.org>
From: Fabiano Rosas <farosas@linux.ibm.com>
[ Upstream commit 05e6295dc7de859c9d56334805485c4d20bebf25 ]
The current nested KVM code does not support HPT guests. This is
informed/enforced in some ways:
- Hosts < P9 will not be able to enable the nested HV feature;
- The nested hypervisor MMU capabilities will not contain
KVM_CAP_PPC_MMU_HASH_V3;
- QEMU reflects the MMU capabilities in the
'ibm,arch-vec-5-platform-support' device-tree property;
- The nested guest, at 'prom_parse_mmu_model' ignores the
'disable_radix' kernel command line option if HPT is not supported;
- The KVM_PPC_CONFIGURE_V3_MMU ioctl will fail if trying to use HPT.
There is, however, still a way to start a HPT guest by using
max-compat-cpu=power8 at the QEMU machine options. This leads to the
guest being set to use hash after QEMU calls the KVM_PPC_ALLOCATE_HTAB
ioctl.
With the guest set to hash, the nested hypervisor goes through the
entry path that has no knowledge of nesting (kvmppc_run_vcpu) and
crashes when it tries to execute an hypervisor-privileged (mtspr
HDEC) instruction at __kvmppc_vcore_entry:
root@L1:~ $ qemu-system-ppc64 -machine pseries,max-cpu-compat=power8 ...
<snip>
[ 538.543303] CPU: 83 PID: 25185 Comm: CPU 0/KVM Not tainted 5.9.0-rc4 #1
[ 538.543355] NIP: c00800000753f388 LR: c00800000753f368 CTR: c0000000001e5ec0
[ 538.543417] REGS: c0000013e91e33b0 TRAP: 0700 Not tainted (5.9.0-rc4)
[ 538.543470] MSR: 8000000002843033 <SF,VEC,VSX,FP,ME,IR,DR,RI,LE> CR: 22422882 XER: 20040000
[ 538.543546] CFAR: c00800000753f4b0 IRQMASK: 3
GPR00: c0080000075397a0 c0000013e91e3640 c00800000755e600 0000000080000000
GPR04: 0000000000000000 c0000013eab19800 c000001394de0000 00000043a054db72
GPR08: 00000000003b1652 0000000000000000 0000000000000000 c0080000075502e0
GPR12: c0000000001e5ec0 c0000007ffa74200 c0000013eab19800 0000000000000008
GPR16: 0000000000000000 c00000139676c6c0 c000000001d23948 c0000013e91e38b8
GPR20: 0000000000000053 0000000000000000 0000000000000001 0000000000000000
GPR24: 0000000000000001 0000000000000001 0000000000000000 0000000000000001
GPR28: 0000000000000001 0000000000000053 c0000013eab19800 0000000000000001
[ 538.544067] NIP [c00800000753f388] __kvmppc_vcore_entry+0x90/0x104 [kvm_hv]
[ 538.544121] LR [c00800000753f368] __kvmppc_vcore_entry+0x70/0x104 [kvm_hv]
[ 538.544173] Call Trace:
[ 538.544196] [c0000013e91e3640] [c0000013e91e3680] 0xc0000013e91e3680 (unreliable)
[ 538.544260] [c0000013e91e3820] [c0080000075397a0] kvmppc_run_core+0xbc8/0x19d0 [kvm_hv]
[ 538.544325] [c0000013e91e39e0] [c00800000753d99c] kvmppc_vcpu_run_hv+0x404/0xc00 [kvm_hv]
[ 538.544394] [c0000013e91e3ad0] [c0080000072da4fc] kvmppc_vcpu_run+0x34/0x48 [kvm]
[ 538.544472] [c0000013e91e3af0] [c0080000072d61b8] kvm_arch_vcpu_ioctl_run+0x310/0x420 [kvm]
[ 538.544539] [c0000013e91e3b80] [c0080000072c7450] kvm_vcpu_ioctl+0x298/0x778 [kvm]
[ 538.544605] [c0000013e91e3ce0] [c0000000004b8c2c] sys_ioctl+0x1dc/0xc90
[ 538.544662] [c0000013e91e3dc0] [c00000000002f9a4] system_call_exception+0xe4/0x1c0
[ 538.544726] [c0000013e91e3e20] [c00000000000d140] system_call_common+0xf0/0x27c
[ 538.544787] Instruction dump:
[ 538.544821] f86d1098 60000000 60000000 48000099 e8ad0fe8 e8c500a0 e9264140 75290002
[ 538.544886] 7d1602a6 7cec42a6 40820008 7d0807b4 <7d164ba6> 7d083a14 f90d10a0 480104fd
[ 538.544953] ---[ end trace 74423e2b948c2e0c ]---
This patch makes the KVM_PPC_ALLOCATE_HTAB ioctl fail when running in
the nested hypervisor, causing QEMU to abort.
Reported-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kvm/book3s_hv.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index e2183fed947d4..dd9b19b1f459a 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -5191,6 +5191,12 @@ static long kvm_arch_vm_ioctl_hv(struct file *filp,
case KVM_PPC_ALLOCATE_HTAB: {
u32 htab_order;
+ /* If we're a nested hypervisor, we currently only support radix */
+ if (kvmhv_on_pseries()) {
+ r = -EOPNOTSUPP;
+ break;
+ }
+
r = -EFAULT;
if (get_user(htab_order, (u32 __user *)argp))
break;
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 4.19 01/60] powerpc/powernv/smp: Fix spurious DBG() warning
From: Sasha Levin @ 2020-10-27 0:03 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, linuxppc-dev, Oliver O'Halloran, Joel Stanley
From: Oliver O'Halloran <oohall@gmail.com>
[ Upstream commit f6bac19cf65c5be21d14a0c9684c8f560f2096dd ]
When building with W=1 we get the following warning:
arch/powerpc/platforms/powernv/smp.c: In function ‘pnv_smp_cpu_kill_self’:
arch/powerpc/platforms/powernv/smp.c:276:16: error: suggest braces around
empty body in an ‘if’ statement [-Werror=empty-body]
276 | cpu, srr1);
| ^
cc1: all warnings being treated as errors
The full context is this block:
if (srr1 && !generic_check_cpu_restart(cpu))
DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
cpu, srr1);
When building with DEBUG undefined DBG() expands to nothing and GCC emits
the warning due to the lack of braces around an empty statement.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-2-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/powernv/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index 8d49ba370c504..889c3dbec6fb9 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -47,7 +47,7 @@
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
-#define DBG(fmt...)
+#define DBG(fmt...) do { } while (0)
#endif
static void pnv_smp_setup_cpu(int cpu)
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 4.19 02/60] powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
From: Sasha Levin @ 2020-10-27 0:03 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev, Nicholas Piggin
In-Reply-To: <20201027000415.1026364-1-sashal@kernel.org>
From: Nicholas Piggin <npiggin@gmail.com>
[ Upstream commit 66acd46080bd9e5ad2be4b0eb1d498d5145d058e ]
powerpc uses IPIs in some situations to switch a kernel thread away
from a lazy tlb mm, which is subject to the TLB flushing race
described in the changelog introducing ARCH_WANT_IRQS_OFF_ACTIVATE_MM.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-3-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/mmu_context.h | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index f38d153d25861..0bc53f0e37c0f 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -152,6 +152,7 @@ config PPC
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF if PPC64
select ARCH_WANT_IPC_PARSE_VERSION
+ select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
select ARCH_WEAK_RELEASE_ACQUIRE
select BINFMT_ELF
select BUILDTIME_EXTABLE_SORT
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index ae953958c0f33..d93bdcaa4a469 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -204,7 +204,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
*/
static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
- switch_mm(prev, next, current);
+ switch_mm_irqs_off(prev, next, current);
}
/* We don't currently use enter_lazy_tlb() for anything */
--
2.25.1
^ permalink raw reply related
* Re: [REGRESSION] mm: process_vm_readv testcase no longer works after compat_prcoess_vm_readv removed
From: Jens Axboe @ 2020-10-26 23:56 UTC (permalink / raw)
To: Kyle Huey, open list, Christoph Hellwig
Cc: linux-aio, David Howells, linux-mm, keyrings, sparclinux,
Robert O'Callahan, linux-arch, linux-s390, linux-scsi,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT), Linus Torvalds,
Arnd Bergmann, linux-block, Alexander Viro, io-uring,
moderated list:ARM PORT, linux-parisc, netdev, linux-mips,
linux-security-module,
open list:FILESYSTEMS (VFS and infrastructure), Andrew Morton,
linuxppc-dev
In-Reply-To: <CAP045Aqrsb=CXHDHx4nS-pgg+MUDj14r-kN8_Jcbn-NAUziVag@mail.gmail.com>
On 10/26/20 4:55 PM, Kyle Huey wrote:
> A test program from the rr[0] test suite, vm_readv_writev[1], no
> longer works on 5.10-rc1 when compiled as a 32 bit binary and executed
> on a 64 bit kernel. The first process_vm_readv call (on line 35) now
> fails with EFAULT. I have bisected this to
> c3973b401ef2b0b8005f8074a10e96e3ea093823.
>
> It should be fairly straightforward to extract the test case from our
> repository into a standalone program.
Can you check with this applied?
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index fd12da80b6f2..05676722d9cd 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -273,7 +273,8 @@ static ssize_t process_vm_rw(pid_t pid,
return rc;
if (!iov_iter_count(&iter))
goto free_iov_l;
- iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r, false);
+ iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r,
+ in_compat_syscall());
if (IS_ERR(iov_r)) {
rc = PTR_ERR(iov_r);
goto free_iov_l;
--
Jens Axboe
^ permalink raw reply related
* Re: [REGRESSION] mm: process_vm_readv testcase no longer works after compat_prcoess_vm_readv removed
From: Al Viro @ 2020-10-27 0:05 UTC (permalink / raw)
To: Jens Axboe
Cc: linux-aio, linux-mips, David Howells, linux-mm, keyrings,
sparclinux, Christoph Hellwig, linux-arch, linux-s390, linux-scsi,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
linux-security-module, Robert O'Callahan, Linus Torvalds,
Arnd Bergmann, linux-block, io-uring, moderated list:ARM PORT,
linux-parisc, netdev, open list, Kyle Huey,
open list:FILESYSTEMS (VFS and infrastructure), Andrew Morton,
linuxppc-dev
In-Reply-To: <70d5569e-4ad6-988a-e047-5d12d298684c@kernel.dk>
On Mon, Oct 26, 2020 at 05:56:11PM -0600, Jens Axboe wrote:
> On 10/26/20 4:55 PM, Kyle Huey wrote:
> > A test program from the rr[0] test suite, vm_readv_writev[1], no
> > longer works on 5.10-rc1 when compiled as a 32 bit binary and executed
> > on a 64 bit kernel. The first process_vm_readv call (on line 35) now
> > fails with EFAULT. I have bisected this to
> > c3973b401ef2b0b8005f8074a10e96e3ea093823.
> >
> > It should be fairly straightforward to extract the test case from our
> > repository into a standalone program.
>
> Can you check with this applied?
>
> diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
> index fd12da80b6f2..05676722d9cd 100644
> --- a/mm/process_vm_access.c
> +++ b/mm/process_vm_access.c
> @@ -273,7 +273,8 @@ static ssize_t process_vm_rw(pid_t pid,
> return rc;
> if (!iov_iter_count(&iter))
> goto free_iov_l;
> - iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r, false);
> + iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r,
> + in_compat_syscall());
_ouch_
There's a bug, all right, but I'm not sure that this is all there is to it.
For now it's probably the right fix, but... Consider the fun trying to
use that from 32bit process to access the memory of 64bit one. IOW, we
might want to add an explicit flag for "force 64bit addresses/sizes
in rvec".
^ permalink raw reply
* Re: [REGRESSION] mm: process_vm_readv testcase no longer works after compat_prcoess_vm_readv removed
From: Jens Axboe @ 2020-10-27 0:09 UTC (permalink / raw)
To: Al Viro
Cc: linux-aio, linux-mips, David Howells, linux-mm, keyrings,
sparclinux, Christoph Hellwig, linux-arch, linux-s390, linux-scsi,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
linux-security-module, Robert O'Callahan, Linus Torvalds,
Arnd Bergmann, linux-block, io-uring, moderated list:ARM PORT,
linux-parisc, netdev, open list, Kyle Huey,
open list:FILESYSTEMS (VFS and infrastructure), Andrew Morton,
linuxppc-dev
In-Reply-To: <20201027000521.GD3576660@ZenIV.linux.org.uk>
On 10/26/20 6:05 PM, Al Viro wrote:
> On Mon, Oct 26, 2020 at 05:56:11PM -0600, Jens Axboe wrote:
>> On 10/26/20 4:55 PM, Kyle Huey wrote:
>>> A test program from the rr[0] test suite, vm_readv_writev[1], no
>>> longer works on 5.10-rc1 when compiled as a 32 bit binary and executed
>>> on a 64 bit kernel. The first process_vm_readv call (on line 35) now
>>> fails with EFAULT. I have bisected this to
>>> c3973b401ef2b0b8005f8074a10e96e3ea093823.
>>>
>>> It should be fairly straightforward to extract the test case from our
>>> repository into a standalone program.
>>
>> Can you check with this applied?
>>
>> diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
>> index fd12da80b6f2..05676722d9cd 100644
>> --- a/mm/process_vm_access.c
>> +++ b/mm/process_vm_access.c
>> @@ -273,7 +273,8 @@ static ssize_t process_vm_rw(pid_t pid,
>> return rc;
>> if (!iov_iter_count(&iter))
>> goto free_iov_l;
>> - iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r, false);
>> + iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r,
>> + in_compat_syscall());
>
> _ouch_
>
> There's a bug, all right, but I'm not sure that this is all there is
> to it. For now it's probably the right fix, but... Consider the fun
> trying to use that from 32bit process to access the memory of 64bit
> one. IOW, we might want to add an explicit flag for "force 64bit
> addresses/sizes in rvec".
Ouch yes good point, nice catch.
--
Jens Axboe
^ permalink raw reply
* [PATCH AUTOSEL 4.14 01/46] powerpc/powernv/smp: Fix spurious DBG() warning
From: Sasha Levin @ 2020-10-27 0:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, linuxppc-dev, Oliver O'Halloran, Joel Stanley
From: Oliver O'Halloran <oohall@gmail.com>
[ Upstream commit f6bac19cf65c5be21d14a0c9684c8f560f2096dd ]
When building with W=1 we get the following warning:
arch/powerpc/platforms/powernv/smp.c: In function ‘pnv_smp_cpu_kill_self’:
arch/powerpc/platforms/powernv/smp.c:276:16: error: suggest braces around
empty body in an ‘if’ statement [-Werror=empty-body]
276 | cpu, srr1);
| ^
cc1: all warnings being treated as errors
The full context is this block:
if (srr1 && !generic_check_cpu_restart(cpu))
DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
cpu, srr1);
When building with DEBUG undefined DBG() expands to nothing and GCC emits
the warning due to the lack of braces around an empty statement.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-2-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/powernv/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index c17f81e433f7d..11d8fde770c38 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -44,7 +44,7 @@
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
-#define DBG(fmt...)
+#define DBG(fmt...) do { } while (0)
#endif
static void pnv_smp_setup_cpu(int cpu)
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 4.14 02/46] powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
From: Sasha Levin @ 2020-10-27 0:09 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev, Nicholas Piggin
In-Reply-To: <20201027000946.1026923-1-sashal@kernel.org>
From: Nicholas Piggin <npiggin@gmail.com>
[ Upstream commit 66acd46080bd9e5ad2be4b0eb1d498d5145d058e ]
powerpc uses IPIs in some situations to switch a kernel thread away
from a lazy tlb mm, which is subject to the TLB flushing race
described in the changelog introducing ARCH_WANT_IRQS_OFF_ACTIVATE_MM.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-3-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/mmu_context.h | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 679e1e3c16953..7cc91d7f893cf 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -154,6 +154,7 @@ config PPC
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF if PPC64
select ARCH_WANT_IPC_PARSE_VERSION
+ select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
select ARCH_WEAK_RELEASE_ACQUIRE
select BINFMT_ELF
select BUILDTIME_EXTABLE_SORT
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 6f67ff5a52672..5f9ad4f4b9c0f 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -101,7 +101,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
*/
static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
- switch_mm(prev, next, current);
+ switch_mm_irqs_off(prev, next, current);
}
/* We don't currently use enter_lazy_tlb() for anything */
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 4.9 01/30] powerpc/powernv/smp: Fix spurious DBG() warning
From: Sasha Levin @ 2020-10-27 0:10 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, linuxppc-dev, Oliver O'Halloran, Joel Stanley
From: Oliver O'Halloran <oohall@gmail.com>
[ Upstream commit f6bac19cf65c5be21d14a0c9684c8f560f2096dd ]
When building with W=1 we get the following warning:
arch/powerpc/platforms/powernv/smp.c: In function ‘pnv_smp_cpu_kill_self’:
arch/powerpc/platforms/powernv/smp.c:276:16: error: suggest braces around
empty body in an ‘if’ statement [-Werror=empty-body]
276 | cpu, srr1);
| ^
cc1: all warnings being treated as errors
The full context is this block:
if (srr1 && !generic_check_cpu_restart(cpu))
DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
cpu, srr1);
When building with DEBUG undefined DBG() expands to nothing and GCC emits
the warning due to the lack of braces around an empty statement.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-2-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/powernv/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index eec0e8d0454d1..7e0f5fa0452b3 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -41,7 +41,7 @@
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
-#define DBG(fmt...)
+#define DBG(fmt...) do { } while (0)
#endif
static void pnv_smp_setup_cpu(int cpu)
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 4.4 01/25] powerpc/powernv/smp: Fix spurious DBG() warning
From: Sasha Levin @ 2020-10-27 0:10 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, linuxppc-dev, Oliver O'Halloran, Joel Stanley
From: Oliver O'Halloran <oohall@gmail.com>
[ Upstream commit f6bac19cf65c5be21d14a0c9684c8f560f2096dd ]
When building with W=1 we get the following warning:
arch/powerpc/platforms/powernv/smp.c: In function ‘pnv_smp_cpu_kill_self’:
arch/powerpc/platforms/powernv/smp.c:276:16: error: suggest braces around
empty body in an ‘if’ statement [-Werror=empty-body]
276 | cpu, srr1);
| ^
cc1: all warnings being treated as errors
The full context is this block:
if (srr1 && !generic_check_cpu_restart(cpu))
DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
cpu, srr1);
When building with DEBUG undefined DBG() expands to nothing and GCC emits
the warning due to the lack of braces around an empty statement.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-2-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/powernv/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index ad7b1a3dbed09..c605c78a80896 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -41,7 +41,7 @@
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
-#define DBG(fmt...)
+#define DBG(fmt...) do { } while (0)
#endif
static void pnv_smp_setup_cpu(int cpu)
--
2.25.1
^ permalink raw reply related
* [PATCH AUTOSEL 4.4 21/25] KVM: PPC: Book3S HV: Do not allocate HPT for a nested guest
From: Sasha Levin @ 2020-10-27 0:11 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, Fabiano Rosas, Greg Kurz, kvm-ppc,
Satheesh Rajendran, linuxppc-dev, David Gibson
In-Reply-To: <20201027001123.1027642-1-sashal@kernel.org>
From: Fabiano Rosas <farosas@linux.ibm.com>
[ Upstream commit 05e6295dc7de859c9d56334805485c4d20bebf25 ]
The current nested KVM code does not support HPT guests. This is
informed/enforced in some ways:
- Hosts < P9 will not be able to enable the nested HV feature;
- The nested hypervisor MMU capabilities will not contain
KVM_CAP_PPC_MMU_HASH_V3;
- QEMU reflects the MMU capabilities in the
'ibm,arch-vec-5-platform-support' device-tree property;
- The nested guest, at 'prom_parse_mmu_model' ignores the
'disable_radix' kernel command line option if HPT is not supported;
- The KVM_PPC_CONFIGURE_V3_MMU ioctl will fail if trying to use HPT.
There is, however, still a way to start a HPT guest by using
max-compat-cpu=power8 at the QEMU machine options. This leads to the
guest being set to use hash after QEMU calls the KVM_PPC_ALLOCATE_HTAB
ioctl.
With the guest set to hash, the nested hypervisor goes through the
entry path that has no knowledge of nesting (kvmppc_run_vcpu) and
crashes when it tries to execute an hypervisor-privileged (mtspr
HDEC) instruction at __kvmppc_vcore_entry:
root@L1:~ $ qemu-system-ppc64 -machine pseries,max-cpu-compat=power8 ...
<snip>
[ 538.543303] CPU: 83 PID: 25185 Comm: CPU 0/KVM Not tainted 5.9.0-rc4 #1
[ 538.543355] NIP: c00800000753f388 LR: c00800000753f368 CTR: c0000000001e5ec0
[ 538.543417] REGS: c0000013e91e33b0 TRAP: 0700 Not tainted (5.9.0-rc4)
[ 538.543470] MSR: 8000000002843033 <SF,VEC,VSX,FP,ME,IR,DR,RI,LE> CR: 22422882 XER: 20040000
[ 538.543546] CFAR: c00800000753f4b0 IRQMASK: 3
GPR00: c0080000075397a0 c0000013e91e3640 c00800000755e600 0000000080000000
GPR04: 0000000000000000 c0000013eab19800 c000001394de0000 00000043a054db72
GPR08: 00000000003b1652 0000000000000000 0000000000000000 c0080000075502e0
GPR12: c0000000001e5ec0 c0000007ffa74200 c0000013eab19800 0000000000000008
GPR16: 0000000000000000 c00000139676c6c0 c000000001d23948 c0000013e91e38b8
GPR20: 0000000000000053 0000000000000000 0000000000000001 0000000000000000
GPR24: 0000000000000001 0000000000000001 0000000000000000 0000000000000001
GPR28: 0000000000000001 0000000000000053 c0000013eab19800 0000000000000001
[ 538.544067] NIP [c00800000753f388] __kvmppc_vcore_entry+0x90/0x104 [kvm_hv]
[ 538.544121] LR [c00800000753f368] __kvmppc_vcore_entry+0x70/0x104 [kvm_hv]
[ 538.544173] Call Trace:
[ 538.544196] [c0000013e91e3640] [c0000013e91e3680] 0xc0000013e91e3680 (unreliable)
[ 538.544260] [c0000013e91e3820] [c0080000075397a0] kvmppc_run_core+0xbc8/0x19d0 [kvm_hv]
[ 538.544325] [c0000013e91e39e0] [c00800000753d99c] kvmppc_vcpu_run_hv+0x404/0xc00 [kvm_hv]
[ 538.544394] [c0000013e91e3ad0] [c0080000072da4fc] kvmppc_vcpu_run+0x34/0x48 [kvm]
[ 538.544472] [c0000013e91e3af0] [c0080000072d61b8] kvm_arch_vcpu_ioctl_run+0x310/0x420 [kvm]
[ 538.544539] [c0000013e91e3b80] [c0080000072c7450] kvm_vcpu_ioctl+0x298/0x778 [kvm]
[ 538.544605] [c0000013e91e3ce0] [c0000000004b8c2c] sys_ioctl+0x1dc/0xc90
[ 538.544662] [c0000013e91e3dc0] [c00000000002f9a4] system_call_exception+0xe4/0x1c0
[ 538.544726] [c0000013e91e3e20] [c00000000000d140] system_call_common+0xf0/0x27c
[ 538.544787] Instruction dump:
[ 538.544821] f86d1098 60000000 60000000 48000099 e8ad0fe8 e8c500a0 e9264140 75290002
[ 538.544886] 7d1602a6 7cec42a6 40820008 7d0807b4 <7d164ba6> 7d083a14 f90d10a0 480104fd
[ 538.544953] ---[ end trace 74423e2b948c2e0c ]---
This patch makes the KVM_PPC_ALLOCATE_HTAB ioctl fail when running in
the nested hypervisor, causing QEMU to abort.
Reported-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kvm/book3s_hv.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 54c6ba87a25ad..b005ce9dc8f04 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3157,6 +3157,12 @@ static long kvm_arch_vm_ioctl_hv(struct file *filp,
case KVM_PPC_ALLOCATE_HTAB: {
u32 htab_order;
+ /* If we're a nested hypervisor, we currently only support radix */
+ if (kvmhv_on_pseries()) {
+ r = -EOPNOTSUPP;
+ break;
+ }
+
r = -EFAULT;
if (get_user(htab_order, (u32 __user *)argp))
break;
--
2.25.1
^ permalink raw reply related
* Re: [PATCH 2/4] PM: hibernate: improve robustness of mapping pages in the direct map
From: Edgecombe, Rick P @ 2020-10-27 1:10 UTC (permalink / raw)
To: rppt@kernel.org
Cc: david@redhat.com, peterz@infradead.org, catalin.marinas@arm.com,
dave.hansen@linux.intel.com, linux-mm@kvack.org, paulus@samba.org,
pavel@ucw.cz, hpa@zytor.com, sparclinux@vger.kernel.org,
cl@linux.com, will@kernel.org, linux-riscv@lists.infradead.org,
linux-s390@vger.kernel.org, x86@kernel.org, rppt@linux.ibm.com,
borntraeger@de.ibm.com, mingo@redhat.com, rientjes@google.com,
Brown, Len, aou@eecs.berkeley.edu, gor@linux.ibm.com,
linux-pm@vger.kernel.org, hca@linux.ibm.com, bp@alien8.de,
luto@kernel.org, paul.walmsley@sifive.com, kirill@shutemov.name,
tglx@linutronix.de, iamjoonsoo.kim@lge.com,
linux-arm-kernel@lists.infradead.org, rjw@rjwysocki.net,
linux-kernel@vger.kernel.org, penberg@kernel.org,
palmer@dabbelt.com, akpm@linux-foundation.org,
linuxppc-dev@lists.ozlabs.org, davem@davemloft.net
In-Reply-To: <20201026091554.GB1154158@kernel.org>
On Mon, 2020-10-26 at 11:15 +0200, Mike Rapoport wrote:
> The intention of this series is to disallow usage of
> __kernel_map_pages() when DEBUG_PAGEALLOC=n. I'll update this patch
> to
> better handle possible errors, but I still want to keep WARN in the
> caller.
Sorry, I missed this snippet at the bottom, that your intention was to
actually handle errors somehow in the hibernate code. Please ignore my
other comment that assumed you wanted to just add a warn.
^ permalink raw reply
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