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[Qemu-devel] [PULL v6 20/42] deprecate -mem-path fallback to anonymous R
From: |
Eduardo Habkost |
Subject: |
[Qemu-devel] [PULL v6 20/42] deprecate -mem-path fallback to anonymous RAM |
Date: |
Fri, 5 Jul 2019 19:14:42 -0300 |
From: Igor Mammedov <address@hidden>
Fallback might affect guest or worse whole host performance
or functionality if backing file were used to share guest RAM
with another process.
Patch deprecates fallback so that we could remove it in future
and ensure that QEMU will provide expected behavior and fail if
it can't use user provided backing file.
Signed-off-by: Igor Mammedov <address@hidden>
Reviewed-by: Daniel P. Berrangé <address@hidden>
Reviewed-by: Markus Armbruster <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
Signed-off-by: Eduardo Habkost <address@hidden>
---
hw/core/numa.c | 6 ++++--
qemu-deprecated.texi | 9 +++++++++
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/hw/core/numa.c b/hw/core/numa.c
index cb5fdbcb1e..dd5c6e2334 100644
--- a/hw/core/numa.c
+++ b/hw/core/numa.c
@@ -479,8 +479,10 @@ static void allocate_system_memory_nonnuma(MemoryRegion
*mr, Object *owner,
if (mem_prealloc) {
exit(1);
}
- error_report("falling back to regular RAM allocation.");
-
+ warn_report("falling back to regular RAM allocation");
+ error_printf("This is deprecated. Make sure that -mem-path "
+ " specified path has sufficient resources to allocate"
+ " -m specified RAM amount");
/* Legacy behavior: if allocation failed, fall back to
* regular RAM allocation.
*/
diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
index 4a626f535d..e6891c3a93 100644
--- a/qemu-deprecated.texi
+++ b/qemu-deprecated.texi
@@ -112,6 +112,15 @@ QEMU using implicit generic or board specific splitting
rule.
Use @option{memdev} with @var{memory-backend-ram} backend or @option{mem} (if
it's supported by used machine type) to define mapping explictly instead.
+@subsection -mem-path fallback to RAM (since 4.1)
+Currently if guest RAM allocation from file pointed by @option{mem-path}
+fails, QEMU falls back to allocating from RAM, which might result
+in unpredictable behavior since the backing file specified by the user
+is ignored. In the future, users will be responsible for making sure
+the backing storage specified with @option{-mem-path} can actually provide
+the guest RAM configured with @option{-m} and QEMU will fail to start up if
+RAM allocation is unsuccessful.
+
@section QEMU Machine Protocol (QMP) commands
@subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
--
2.18.0.rc1.1.g3f1ff2140
- [Qemu-devel] [PULL v6 14/42] i386: Update new x86_apicid parsing rules with die_offset support, (continued)
- [Qemu-devel] [PULL v6 14/42] i386: Update new x86_apicid parsing rules with die_offset support, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 17/42] numa: deprecate 'mem' parameter of '-numa node' option, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 18/42] numa: deprecate implict memory distribution between nodes, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 19/42] hppa: Delete unused hppa_cpu_list() function, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 21/42] i386: Don't print warning if phys-bits was set automatically, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 22/42] i386: Fix signedness of hyperv_spinlock_attempts, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 24/42] x86/cpu: use FeatureWordArray to define filtered_features, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 23/42] i386: make 'hv-spinlocks' a regular uint32 property, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 25/42] i386: Remove unused host_cpudef variable, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 26/42] target/i386: Add CPUID.1F generation support for multi-dies PCMachine, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 20/42] deprecate -mem-path fallback to anonymous RAM,
Eduardo Habkost <=
- [Qemu-devel] [PULL v6 27/42] machine: Refactor smp_parse() in vl.c as MachineClass::smp_parse(), Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 28/42] vl.c: Add -smp, dies=* command line support and update doc, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 29/42] qmp: Add deprecation information to query-machines, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 30/42] i386: Introduce SnowRidge CPU model, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 31/42] qmp: Add "alias-of" field to query-cpu-definitions, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 34/42] i386: Register versioned CPU models, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 42/42] tests: use -numa memdev option in tests instead of legacy 'mem' option, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 32/42] i386: Add x-force-features option for testing, Eduardo Habkost, 2019/07/05
- [Qemu-devel] [PULL v6 33/42] i386: Get model-id from CPU object on "-cpu help", Eduardo Habkost, 2019/07/05