kernel/virtio: avoid zeroing and extra copying the destination buffer#782
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joergroedel merged 1 commit intococonut-svsm:mainfrom Sep 10, 2025
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@joergroedel done, the results it's much better, thanks for the idea! I don't like much the |
luigix25
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Sep 9, 2025
`SvsmHal::mmio_read()` currently allocates the destination buffer, zeros it, and then copies its value. Avoid all this by allocating `MaybeUninit::<T>` on the stack and passing a `[MaybeUninit<u8>]` reference to `SVSM_PLATFORM.mmio_read()`. Cascade the changes to the functions to use `[MaybeUninit<u8>]`, since the destination buffer may be uninitialized. Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
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While reviewing #775 I figured out that
SvsmHal::mmio_read()could be improved a bit.SvsmHal::mmio_read()currently allocates the destination buffer, zeros it, and then copies its value. Avoid all this by allocatingMaybeUninit::<T>on the stack and passing a pointer toSVSM_PLATFORM.mmio_read().Cascade the changes to the functions to use a pointer, since the destination buffer may be uninitialized.