From 3cab2a638a10ece2b76d9f33a3c5dc6f64f1bbaa Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Wed, 10 May 2023 12:55:31 +0200 Subject: [PATCH 21/21] s390x/pv: Fix spurious warning with asynchronous teardown MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Thomas Huth RH-MergeRequest: 173: Improve memory reclaiming for z15 Secure Execution guests RH-Bugzilla: 2168500 RH-Acked-by: Cornelia Huck RH-Acked-by: Miroslav Rezanina RH-Acked-by: Cédric Le Goater RH-Commit: [2/2] cb690d3155ea22c6df00a4d75b72f501515e5556 (thuth/qemu-kvm-cs9) Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2168500 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 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 Message-Id: <20230510105531.30623-2-imbrenda@linux.ibm.com> Reviewed-by: Thomas Huth [thuth: Fix inline function parameter in pv.h] Signed-off-by: Thomas Huth (cherry picked from commit 88693ab2a53f2f3d25cb39a7b5034ab391bc5a81) --- hw/s390x/pv.c | 10 ++++++++-- hw/s390x/s390-virtio-ccw.c | 2 +- include/hw/s390x/pv.h | 6 +++--- 3 files changed, 12 insertions(+), 6 deletions(-) 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 +#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 6a0b93c63d..d95c595f88 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..7b935e2246 100644 --- a/include/hw/s390x/pv.h +++ b/include/hw/s390x/pv.h @@ -14,10 +14,10 @@ #include "qapi/error.h" #include "sysemu/kvm.h" +#include "hw/s390x/s390-virtio-ccw.h" #ifdef CONFIG_KVM #include "cpu.h" -#include "hw/s390x/s390-virtio-ccw.h" static inline bool s390_is_pv(void) { @@ -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); @@ -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) {} -- 2.39.3