| Message ID | 20230510105531.30623-2-imbrenda@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390x/pv: Fix spurious warning with asynchronous teardown | expand |
On 10/05/2023 12.55, Claudio Imbrenda wrote: > Kernel commit 292a7d6fca33 ("KVM: s390: pv: fix asynchronous teardown > for small VMs") causes the KVM_PV_ASYNC_CLEANUP_PREPARE ioctl to fail > if the VM is not larger than 2GiB. QEMU would attempt it and fail, > print an error message, and then proceed with a normal teardown. > > Avoid attempting to use asynchronous teardown altogether when the VM is > not larger than 2 GiB. This will avoid triggering the error message and > also avoid pointless overhead; normal teardown is fast enough for small > VMs. > > Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com> > Fixes: c3a073c610 ("s390x/pv: Add support for asynchronous teardown for reboot") > Link: https://lore.kernel.org/all/20230421085036.52511-2-imbrenda@linux.ibm.com/ > Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > --- > hw/s390x/pv.c | 10 ++++++++-- > hw/s390x/s390-virtio-ccw.c | 2 +- > include/hw/s390x/pv.h | 2 +- > 3 files changed, 10 insertions(+), 4 deletions(-) Reviewed-by: Thomas Huth <thuth@redhat.com>
On 10/05/2023 12.55, Claudio Imbrenda wrote: > Kernel commit 292a7d6fca33 ("KVM: s390: pv: fix asynchronous teardown > for small VMs") causes the KVM_PV_ASYNC_CLEANUP_PREPARE ioctl to fail > if the VM is not larger than 2GiB. QEMU would attempt it and fail, > print an error message, and then proceed with a normal teardown. > > Avoid attempting to use asynchronous teardown altogether when the VM is > not larger than 2 GiB. This will avoid triggering the error message and > also avoid pointless overhead; normal teardown is fast enough for small > VMs. > > Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com> > Fixes: c3a073c610 ("s390x/pv: Add support for asynchronous teardown for reboot") > Link: https://lore.kernel.org/all/20230421085036.52511-2-imbrenda@linux.ibm.com/ > Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > --- ... > diff --git a/include/hw/s390x/pv.h b/include/hw/s390x/pv.h > index 966306a9db..6766557fb7 100644 > --- a/include/hw/s390x/pv.h > +++ b/include/hw/s390x/pv.h > @@ -41,7 +41,7 @@ static inline bool s390_is_pv(void) > int s390_pv_query_info(void); > int s390_pv_vm_enable(void); > void s390_pv_vm_disable(void); > -bool s390_pv_vm_try_disable_async(void); > +bool s390_pv_vm_try_disable_async(S390CcwMachineState *ms); > int s390_pv_set_sec_parms(uint64_t origin, uint64_t length); > int s390_pv_unpack(uint64_t addr, uint64_t size, uint64_t tweak); > void s390_pv_prep_reset(void); I'll squash this on top to fix a build failure on non-s390x host systems: diff --git a/include/hw/s390x/pv.h b/include/hw/s390x/pv.h --- a/include/hw/s390x/pv.h +++ b/include/hw/s390x/pv.h @@ -61,7 +61,7 @@ static inline bool s390_is_pv(void) { return false; } static inline int s390_pv_query_info(void) { return 0; } static inline int s390_pv_vm_enable(void) { return 0; } static inline void s390_pv_vm_disable(void) {} -static inline bool s390_pv_vm_try_disable_async(void) { return false; } +static inline bool s390_pv_vm_try_disable_async(S390CcwMachineState *ms) { return false; } static inline int s390_pv_set_sec_parms(uint64_t origin, uint64_t length) { return 0; } static inline int s390_pv_unpack(uint64_t addr, uint64_t size, uint64_t tweak) { return 0; } static inline void s390_pv_prep_reset(void) {} Thomas
diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c index 49ea38236c..b63f3784c6 100644 --- a/hw/s390x/pv.c +++ b/hw/s390x/pv.c @@ -13,6 +13,7 @@ #include <linux/kvm.h> +#include "qemu/units.h" #include "qapi/error.h" #include "qemu/error-report.h" #include "sysemu/kvm.h" @@ -115,7 +116,7 @@ static void *s390_pv_do_unprot_async_fn(void *p) return NULL; } -bool s390_pv_vm_try_disable_async(void) +bool s390_pv_vm_try_disable_async(S390CcwMachineState *ms) { /* * t is only needed to create the thread; once qemu_thread_create @@ -123,7 +124,12 @@ bool s390_pv_vm_try_disable_async(void) */ QemuThread t; - if (!kvm_check_extension(kvm_state, KVM_CAP_S390_PROTECTED_ASYNC_DISABLE)) { + /* + * If the feature is not present or if the VM is not larger than 2 GiB, + * KVM_PV_ASYNC_CLEANUP_PREPARE fill fail; no point in attempting it. + */ + if ((MACHINE(ms)->maxram_size <= 2 * GiB) || + !kvm_check_extension(kvm_state, KVM_CAP_S390_PROTECTED_ASYNC_DISABLE)) { return false; } if (s390_pv_cmd(KVM_PV_ASYNC_CLEANUP_PREPARE, NULL) != 0) { diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c index e6f2c62625..2516b89b32 100644 --- a/hw/s390x/s390-virtio-ccw.c +++ b/hw/s390x/s390-virtio-ccw.c @@ -330,7 +330,7 @@ static inline void s390_do_cpu_ipl(CPUState *cs, run_on_cpu_data arg) static void s390_machine_unprotect(S390CcwMachineState *ms) { - if (!s390_pv_vm_try_disable_async()) { + if (!s390_pv_vm_try_disable_async(ms)) { s390_pv_vm_disable(); } ms->pv = false; diff --git a/include/hw/s390x/pv.h b/include/hw/s390x/pv.h index 966306a9db..6766557fb7 100644 --- a/include/hw/s390x/pv.h +++ b/include/hw/s390x/pv.h @@ -41,7 +41,7 @@ static inline bool s390_is_pv(void) int s390_pv_query_info(void); int s390_pv_vm_enable(void); void s390_pv_vm_disable(void); -bool s390_pv_vm_try_disable_async(void); +bool s390_pv_vm_try_disable_async(S390CcwMachineState *ms); int s390_pv_set_sec_parms(uint64_t origin, uint64_t length); int s390_pv_unpack(uint64_t addr, uint64_t size, uint64_t tweak); void s390_pv_prep_reset(void);
Kernel commit 292a7d6fca33 ("KVM: s390: pv: fix asynchronous teardown for small VMs") causes the KVM_PV_ASYNC_CLEANUP_PREPARE ioctl to fail if the VM is not larger than 2GiB. QEMU would attempt it and fail, print an error message, and then proceed with a normal teardown. Avoid attempting to use asynchronous teardown altogether when the VM is not larger than 2 GiB. This will avoid triggering the error message and also avoid pointless overhead; normal teardown is fast enough for small VMs. Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com> Fixes: c3a073c610 ("s390x/pv: Add support for asynchronous teardown for reboot") Link: https://lore.kernel.org/all/20230421085036.52511-2-imbrenda@linux.ibm.com/ Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> --- hw/s390x/pv.c | 10 ++++++++-- hw/s390x/s390-virtio-ccw.c | 2 +- include/hw/s390x/pv.h | 2 +- 3 files changed, 10 insertions(+), 4 deletions(-)