From c62e79c8ca964aefa5c836d775a3977991336bdc Mon Sep 17 00:00:00 2001 From: Nikolay Shirokovskiy Date: Thu, 9 Jun 2016 17:32:32 +0300 Subject: [PATCH] qemu: Filter cur_balloon ABI check for certain transactions Since the domain lock is not held during preparation of an external XML config, it is possible that the value can change resulting in unexpected failures during ABI consistency checking for some save and migrate operations. This patch adds a new flag to skip the checking of the cur_balloon value and then sets the destination value to the source value to ensure subsequent checks without the skip flag will succeed. This way it is protected from forges and is keeped up to date too. Signed-off-by: Nikolay Shirokovskiy --- src/conf/domain_conf.c | 16 +++++++++++++--- src/conf/domain_conf.h | 13 +++++++++++++ src/libvirt_private.syms | 1 + src/qemu/qemu_domain.c | 15 +++++++++++++-- src/qemu/qemu_driver.c | 3 ++- 5 files changed, 42 insertions(+), 6 deletions(-) diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 61f6dbbbaf..c8c4f61cda 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -18775,8 +18775,9 @@ virDomainDefVcpuCheckAbiStability(virDomainDefPtr src, * validation of custom XML config passed in during migration */ bool -virDomainDefCheckABIStability(virDomainDefPtr src, - virDomainDefPtr dst) +virDomainDefCheckABIStabilityFlags(virDomainDefPtr src, + virDomainDefPtr dst, + unsigned int flags) { size_t i; virErrorPtr err; @@ -18820,7 +18821,8 @@ virDomainDefCheckABIStability(virDomainDefPtr src, virDomainDefGetMemoryInitial(src)); goto error; } - if (src->mem.cur_balloon != dst->mem.cur_balloon) { + if (!(flags & VIR_DOMAIN_DEF_ABI_CHECK_SKIP_VOLATILE) && + src->mem.cur_balloon != dst->mem.cur_balloon) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, _("Target domain current memory %lld does not match source %lld"), dst->mem.cur_balloon, src->mem.cur_balloon); @@ -19264,6 +19266,14 @@ virDomainDefCheckABIStability(virDomainDefPtr src, } +bool +virDomainDefCheckABIStability(virDomainDefPtr src, + virDomainDefPtr dst) +{ + return virDomainDefCheckABIStabilityFlags(src, dst, 0); +} + + static int virDomainDefAddDiskControllersForType(virDomainDefPtr def, int controllerType, diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index b88912508b..0fe4154553 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -2644,6 +2644,15 @@ typedef enum { VIR_DOMAIN_DEF_FORMAT_CLOCK_ADJUST = 1 << 9, } virDomainDefFormatFlags; +/* Use these flags to skip specific domain ABI consistency checks done + * in virDomainDefCheckABIStabilityFlags. + */ +typedef enum { + /* Set when domain lock must be released and there exists the possibility + * that some external action could alter the value, such as cur_balloon. */ + VIR_DOMAIN_DEF_ABI_CHECK_SKIP_VOLATILE = 1 << 0, +} virDomainDefABICheckFlags; + virDomainDeviceDefPtr virDomainDeviceDefParse(const char *xmlStr, const virDomainDef *def, virCapsPtr caps, @@ -2679,6 +2688,10 @@ virDomainObjPtr virDomainObjParseFile(const char *filename, bool virDomainDefCheckABIStability(virDomainDefPtr src, virDomainDefPtr dst); +bool virDomainDefCheckABIStabilityFlags(virDomainDefPtr src, + virDomainDefPtr dst, + unsigned int flags); + int virDomainDefAddImplicitDevices(virDomainDefPtr def); virDomainIOThreadIDDefPtr virDomainIOThreadIDFind(const virDomainDef *def, diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index f9d02ad4a7..d62c74c39e 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -219,6 +219,7 @@ virDomainDefAddController; virDomainDefAddImplicitDevices; virDomainDefAddUSBController; virDomainDefCheckABIStability; +virDomainDefCheckABIStabilityFlags; virDomainDefCompatibleDevice; virDomainDefCopy; virDomainDefFindDevice; diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index c1fb771296..7fce2fcb9f 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -4989,14 +4989,25 @@ qemuDomainDefCheckABIStability(virQEMUDriverPtr driver, { virDomainDefPtr migratableDefSrc = NULL; virDomainDefPtr migratableDefDst = NULL; - const int flags = VIR_DOMAIN_XML_SECURE | VIR_DOMAIN_XML_UPDATE_CPU | VIR_DOMAIN_XML_MIGRATABLE; + const unsigned int flags = VIR_DOMAIN_XML_SECURE | + VIR_DOMAIN_XML_UPDATE_CPU | + VIR_DOMAIN_XML_MIGRATABLE; + const unsigned int check_flags = VIR_DOMAIN_DEF_ABI_CHECK_SKIP_VOLATILE; bool ret = false; if (!(migratableDefSrc = qemuDomainDefCopy(driver, src, flags)) || !(migratableDefDst = qemuDomainDefCopy(driver, dst, flags))) goto cleanup; - ret = virDomainDefCheckABIStability(migratableDefSrc, migratableDefDst); + if (!virDomainDefCheckABIStabilityFlags(migratableDefSrc, + migratableDefDst, + check_flags)) + goto cleanup; + + /* Force update any skipped values from the volatile flag */ + dst->mem.cur_balloon = src->mem.cur_balloon; + + ret = true; cleanup: virDomainDefFree(migratableDefSrc); diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 2efaa2ace9..1d94c5f6b8 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -15279,7 +15279,8 @@ qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot, /* Transitions 5, 6, 8, 9 */ /* Check for ABI compatibility. We need to do this check against * the migratable XML or it will always fail otherwise */ - if (config && !qemuDomainDefCheckABIStability(driver, vm->def, config)) { + if (config && + !qemuDomainDefCheckABIStability(driver, vm->def, config)) { virErrorPtr err = virGetLastError(); if (!(flags & VIR_DOMAIN_SNAPSHOT_REVERT_FORCE)) {