When memory page is converted from private to shared, the original
private memory is back'ed by guest_memfd. Introduce
ram_block_discard_guest_memfd_range() for discarding memory in
guest_memfd.
Originally-from: Isaku Yamahata <isaku.yamahata@intel.com>
Codeveloped-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
---
Changes in v5:
- Collect Reviewed-by from David;
Changes in in v4:
- Drop ram_block_convert_range() and open code its implementation in the
next Patch.
Add KVM guest_memfd support to RAMBlock so both normal hva based memory
and kvm guest memfd based private memory can be associated in one RAMBlock.
Introduce new flag RAM_GUEST_MEMFD. When it's set, it calls KVM ioctl to
create private guest_memfd during RAMBlock setup.
Allocating a new RAM_GUEST_MEMFD flag to instruct the setup of guest memfd
is more flexible and extensible than simply relying on the VM type because
in the future we may have the case that not all the memory of a VM need
guest memfd. As a benefit, it also avoid getting MachineState in memory
subsystem.
Note, RAM_GUEST_MEMFD is supposed to be set for memory backends of
confidential guests, such as TDX VM. How and when to set it for memory
backends will be implemented in the following patches.
Introduce memory_region_has_guest_memfd() to query if the MemoryRegion has
KVM guest_memfd allocated.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
---
Changes in v5:
- Use assert(new_block->guest_memfd < 0) instead of condition check;
- Collect Reviewed-by tag from David;
Changes in v4:
- Add clarification of RAM_GUEST_MEMFD in commit message; (David Hildenbrand)
- refine the return value and error message; (Daniel P. Berrangé)
- remove flags in ram_block_add(); (David Hildenbrand)
Changes in v3:
- rename gmem to guest_memfd;
- close(guest_memfd) when RAMBlock is released; (Daniel P. Berrangé)
- Suqash the patch that introduces memory_region_has_guest_memfd().
Arguments `ram_block` are reassigned to local declarations `block`
without further use. Remove re-assignment to reduce noise.
Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
The Big QEMU Lock (BQL) has many names and they are confusing. The
actual QemuMutex variable is called qemu_global_mutex but it's commonly
referred to as the BQL in discussions and some code comments. The
locking APIs, however, are called qemu_mutex_lock_iothread() and
qemu_mutex_unlock_iothread().
The "iothread" name is historic and comes from when the main thread was
split into into KVM vcpu threads and the "iothread" (now called the main
loop thread). I have contributed to the confusion myself by introducing
a separate --object iothread, a separate concept unrelated to the BQL.
The "iothread" name is no longer appropriate for the BQL. Rename the
locking APIs to:
- void bql_lock(void)
- void bql_unlock(void)
- bool bql_locked(void)
There are more APIs with "iothread" in their names. Subsequent patches
will rename them. There are also comments and documentation that will be
updated in later patches.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Acked-by: Fabiano Rosas <farosas@suse.de>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20240102153529.486531-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Unfortunately Coverity doesn't follow the logic aroung "len" and "l"
variables in stacks finishing with flatview_{read,write}_continue() and
generate a lot of OVERRUN false-positives. When small buffer (2 or 4
bytes) is passed to mem read/write path, Coverity assumes the worst
case of sz=8 in stn_he_p()/ldn_he_p() (defined in
include/qemu/bswap.h), and reports buffer overrun.
To silence these false-positives we have model functions, which hide
real logic from Coverity.
However, it turned out that these new two assertions are enough to
quiet Coverity.
Assertions are better than hiding the logic, so let's drop the
modelling and move to assertions for memory r/w call stacks.
After patch, the sequence
cov-make-library --output-file /tmp/master.xmldb \
scripts/coverity-scan/model.c
cov-build --dir ~/covtmp/master make -j9
cov-analyze --user-model-file /tmp/master.xmldb \
--dir ~/covtmp/master --all --strip-path "$(pwd)
cov-format-errors --dir ~/covtmp/master \
--html-output ~/covtmp/master_html_report
Generate for me the same big set of CIDs excepept for 6 disappeared (so
it becomes even better).
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Acked-by: David Hildenbrand <david@redhat.com>
Message-ID: <20231005140326.332830-1-vsementsov@yandex-team.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The softmmu/ directory contains files specific to system
emulation. Rename it as system/. Update meson rules, the
MAINTAINERS file and all the documentation and comments.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20231004090629.37473-14-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
