[v1] Misc HW patches for 2025-09-02

[PULL 02/39] target/ppc/kvm: Avoid using alloca()

Philippe Mathieu-Daudé posted 39 patches 3 weeks, 5 days ago

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Maintainers: "Philippe Mathieu-Daudé" <philmd@linaro.org>, Richard Henderson <richard.henderson@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, "Alex Bennée" <alex.bennee@linaro.org>, Thomas Huth <thuth@redhat.com>, Markus Armbruster <armbru@redhat.com>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Peter Maydell <peter.maydell@linaro.org>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Alistair Francis <alistair@alistair23.me>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Glenn Miles <milesg@linux.ibm.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Eduardo Habkost <eduardo@habkost.net>, John Snow <jsnow@redhat.com>, Huacai Chen <chenhuacai@kernel.org>, Aurelien Jarno <aurelien@aurel32.net>, Francisco Iglesias <francisco.iglesias@amd.com>, Jason Wang <jasowang@redhat.com>, Dmitry Fleytman <dmitry.fleytman@gmail.com>, Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>, Nicholas Piggin <npiggin@gmail.com>, Aditya Gupta <adityag@linux.ibm.com>, Fam Zheng <fam@euphon.net>, Bin Meng <bmeng.cn@gmail.com>, Laurent Vivier <laurent@vivier.eu>, Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>, Alex Williamson <alex.williamson@redhat.com>, "Cédric Le Goater" <clg@redhat.com>, Pierrick Bouvier <pierrick.bouvier@linaro.org>, Aleksandar Rikalo <arikalo@gmail.com>, Chinmay Rath <rathc@linux.ibm.com>, Harsh Prateek Bora <harshpb@linux.ibm.com>

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[PULL 02/39] target/ppc/kvm: Avoid using alloca()

Posted by Philippe Mathieu-Daudé 3 weeks, 5 days ago

kvmppc_load_htab_chunk() is used for migration, thus is not
a hot path. Use the heap instead of the stack, removing the
alloca() call.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Message-Id: <20250901132626.28639-2-philmd@linaro.org>
---
 target/ppc/kvm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index d145774b09a..2521ff65c6c 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -2760,11 +2760,11 @@ int kvmppc_save_htab(QEMUFile *f, int fd, size_t bufsize, int64_t max_ns)
 int kvmppc_load_htab_chunk(QEMUFile *f, int fd, uint32_t index,
                            uint16_t n_valid, uint16_t n_invalid, Error **errp)
 {
-    struct kvm_get_htab_header *buf;
-    size_t chunksize = sizeof(*buf) + n_valid * HASH_PTE_SIZE_64;
+    size_t chunksize = sizeof(struct kvm_get_htab_header)
+                       + n_valid * HASH_PTE_SIZE_64;
+    g_autofree struct kvm_get_htab_header *buf = g_malloc(chunksize);
     ssize_t rc;
 
-    buf = alloca(chunksize);
     buf->index = index;
     buf->n_valid = n_valid;
     buf->n_invalid = n_invalid;
-- 
2.51.0