This change helps to improve performance in plugin communications by
removing unnecessary communication exchange.
The existing protocol basically requires the plugin to send a request
msg and wait for a reply msg. Prior to this change a plugin had to send
a wait request before it got a wait reply (which typically contains an IO
event notication). Similarly, when the plugin sends a resume request
there's also a resume reply that's sent.
The reply to the resume message serves no worthwhile purpose and can be
removed. In the common case there's also no need for the plugin to send
a wait request message--the prior operation was a resume so both sides
know that the only next legal operation is a wait. Thereforce, crosvm
can send a wait reply message without waiting for the plugin's request.
Another way to look at the situation is that a resume request message is
now answered by a wait reply message, and the overall message exchange
pattern looks less like http and more like async I/O.
The plugin's first call to wait is the one time that a wait request is
sent. This in turn will receive an wait-init reply.
TEST=Ran my diagnostic plugin and confirmed that it still passes (after
working around an 8-byte limitation in crosvm). Run my benchmarking
plugin and observed the time it takes to complete go down by 16.5%.
BUG=None
Change-Id: I9c93ba1d3a8f7814ca952f3dc7239d48675192e2
Signed-off-by: Matt Delco <delco@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1571066
Tested-by: kokoro <noreply+kokoro@google.com>
Tested-by: Matt Delco <delco@google.com>
Reviewed-by: Zach Reizner <zachr@chromium.org>
Remove the double underscore in front of `__has_extension` in crosvm.h.
Double underscores in identifiers are reserved for the compiler's
internal use and as it so happens, `__has_extension` is a macro that
clang defines for code to determine whether the compiler supports a
given feature.
We shouldn't be using double underscores in any of the variable names in
this header file but for now just fix the problematic one so that the
code can actually compile under clang.
BUG=b:80150167
TEST=Compile one of the test plugins with clang
Change-Id: Ibb59e72c968a7f245bd6cc693da99f9263eedf33
Signed-off-by: Chirantan Ekbote <chirantan@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1341100
Reviewed-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
KVM_GET_MSRS may return less MSRs that were requested; do not fail but
instead let callers to know how many were fetched.
BUG=None
TEST=cargo test --features plugin
Change-Id: Ie14a3d38b66bfe34f5279543bea9c6c78423527e
Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1192232
Reviewed-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
This change allows plugin to retrieve and set various VM and VCPU states:
interrupt controller, PIT, LAPIC and MP state.
BUG=b:76083711
TEST=cargo test -p kvm
Change-Id: Ie32a67b0cd4a1f0a19ccd826a6e1c9dc25670f95
Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/986511
Reviewed-by: Zach Reizner <zachr@chromium.org>
This plumbs calls to KVM_GET_SUPPORTED_CPUID and KVM_GET_EMULATED_CPUID
to be available to plugins.
TEST=cargo test --features plugin; cargo test -p kvm
BUG=chromium:800626
Change-Id: I98879599b5f970c6c2720772658689a505d8abe1
Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/938674
Reviewed-by: Zach Reizner <zachr@chromium.org>
The guest may need to check for KVM extensions before blindly using
them.
TEST=cargo test --features plugin; cargo test -p kvm; ./build_test
BUG=chromium:800626
Change-Id: If87b928753cd71adeabac4fc7732c3fce7265834
Reviewed-on: https://chromium-review.googlesource.com/906008
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
The guest expects to be able to read the CPUID, so the plugin process
needs to specify what the CPUID for each VCPU will have.
TEST=cargo test --features plugin; ./build_test
BUG=chromium:800626
Change-Id: I9258540ab2501126c3d8cadbd09b7fc01d19f7a9
Reviewed-on: https://chromium-review.googlesource.com/906006
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Dirty logging is not necessary for every memory region, so the plugin
process should be able to specific exactly which regions it would like
dirty logging enabled for.
TEST=cargo test --features plugin
BUG=chromium:800626
Change-Id: I28b8285357e7de1c8c3a1392bdfdb4853ec5a654
Reviewed-on: https://chromium-review.googlesource.com/900294
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
The MSRs are useful for booting a full operating system that requires
them.
TEST=cargo test --features plugin; cargo test -p kvm; ./build_test
BUG=chromium:800626
Change-Id: I817fbf3e6868c85b373808bd48e568b5b2b458eb
Reviewed-on: https://chromium-review.googlesource.com/897412
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
The debug registers are useful to access for the plugin process in some
cases.
TEST=cargo test --features plugin; cargo test -p kvm; ./build_test
BUG=chromium:800626
Change-Id: I8f3f6c31c6989061a43cef948cf5b4e64bd52d30
Reviewed-on: https://chromium-review.googlesource.com/896945
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
This header file defines the C API used to interface with crosvm as a
plugin process.
TEST=None
BUG=chromium:800626
Change-Id: Ie06b833e25dab8f31f64d8bc8b4b521b61d1ca04
Reviewed-on: https://chromium-review.googlesource.com/764267
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Dmitry Torokhov <dtor@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
