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[Qemu-devel] [PULL v4 21/43] deprecate -mem-path fallback to anonymous R
From: |
Eduardo Habkost |
Subject: |
[Qemu-devel] [PULL v4 21/43] deprecate -mem-path fallback to anonymous RAM |
Date: |
Wed, 3 Jul 2019 15:07:04 -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>
---
numa.c | 6 ++++--
qemu-deprecated.texi | 9 +++++++++
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/numa.c b/numa.c
index c1f5e84fa5..48fd43ecc6 100644
--- a/numa.c
+++ b/numa.c
@@ -495,8 +495,10 @@ 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 2fe9b72121..9cba82d5ec 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 v4 10/43] vl.c: Replace smp global variables with smp machine properties, (continued)
- [Qemu-devel] [PULL v4 10/43] vl.c: Replace smp global variables with smp machine properties, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 09/43] hw: Replace global smp variables with MachineState for all remaining archs, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 11/43] i386: Add die-level cpu topology to x86CPU on PCMachine, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 12/43] hw/i386: Adjust nr_dies with configured smp_dies for PCMachine, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 15/43] pc: fix possible NULL pointer dereference in pc_machine_get_device_memory_region_size(), Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 13/43] i386/cpu: Consolidate die-id validity in smp context, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 14/43] i386: Update new x86_apicid parsing rules with die_offset support, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 16/43] machine: show if CLI option '-numa node, mem' is supported in QAPI schema, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 17/43] numa: deprecate 'mem' parameter of '-numa node' option, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 19/43] hppa: Delete unused hppa_cpu_list() function, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 21/43] deprecate -mem-path fallback to anonymous RAM,
Eduardo Habkost <=
- [Qemu-devel] [PULL v4 22/43] i386: Don't print warning if phys-bits was set automatically, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 18/43] numa: deprecate implict memory distribution between nodes, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 20/43] target/i386: fix feature check in hyperv-stub.c, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 25/43] x86/cpu: use FeatureWordArray to define filtered_features, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 24/43] i386: make 'hv-spinlocks' a regular uint32 property, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 31/43] i386: Introduce SnowRidge CPU model, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 23/43] i386: Fix signedness of hyperv_spinlock_attempts, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 32/43] qmp: Add "alias-of" field to query-cpu-definitions, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 34/43] i386: Get model-id from CPU object on "-cpu help", Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 26/43] i386: Remove unused host_cpudef variable, Eduardo Habkost, 2019/07/03