From: Marek Marczykowski-Górecki <marma...@invisiblethingslab.com> Kernel on Xen is loaded via fw_cfg. Previously it used non-DMA version, which loaded the kernel (and initramfs) byte by byte. Change this to DMA, to load in bigger chunks. This change alone reduces load time of a (big) kernel+initramfs from ~10s down to below 1s.
This change was suggested initially here: https://lore.kernel.org/xen-devel/20180216204031.00005...@gmail.com/ Apparently this alone is already enough to get massive speedup. Signed-off-by: Marek Marczykowski-Górecki <marma...@invisiblethingslab.com> Reviewed-by: Alex Bennée <alex.ben...@linaro.org> Reviewed-by: Anthony PERARD <anthony.per...@citrix.com> Message-Id: <20210426034709.595432-1-marma...@invisiblethingslab.com> Signed-off-by: Anthony PERARD <anthony.per...@citrix.com> --- hw/i386/pc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index f5ff970acf..4f322e0856 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -718,7 +718,8 @@ void xen_load_linux(PCMachineState *pcms) assert(MACHINE(pcms)->kernel_filename != NULL); - fw_cfg = fw_cfg_init_io(FW_CFG_IO_BASE); + fw_cfg = fw_cfg_init_io_dma(FW_CFG_IO_BASE, FW_CFG_IO_BASE + 4, + &address_space_memory); fw_cfg_add_i16(fw_cfg, FW_CFG_NB_CPUS, x86ms->boot_cpus); rom_set_fw(fw_cfg); -- Anthony PERARD
