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| author | Stefano Garzarella <sgarzare@redhat.com> | 2018-12-02 14:10:13 +0100 |
|---|---|---|
| committer | Kevin O'Connor <kevin@koconnor.net> | 2018-12-10 22:03:30 -0500 |
| commit | 75b42835134553c96f113e5014072c0caf99d092 (patch) | |
| tree | a22ca8b72057f3dc489c1653eca093c42304f498 /src/fw/paravirt.h | |
| parent | 628b2e6b0e390e26d59b3c5db07a4226175b6f8a (diff) | |
| download | seabios-75b42835134553c96f113e5014072c0caf99d092.tar.gz | |
qemu: avoid debug prints if debugcon is not enabled
In order to speed up the boot phase, we can check the QEMU
debugcon device, and disable the writes if it is not recognized.
This patch allow us to save around 10 msec (time measured
between SeaBIOS entry point and "linuxboot" entry point)
when CONFIG_DEBUG_LEVEL=1 and debugcon is not enabled.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Diffstat (limited to 'src/fw/paravirt.h')
| -rw-r--r-- | src/fw/paravirt.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/fw/paravirt.h b/src/fw/paravirt.h index a14d83e1..f7e1d4c5 100644 --- a/src/fw/paravirt.h +++ b/src/fw/paravirt.h @@ -49,6 +49,9 @@ static inline int runningOnKVM(void) { // QEMU_CFG_DMA ID bit #define QEMU_CFG_VERSION_DMA 2 +// QEMU debugcon read value +#define QEMU_DEBUGCON_READBACK 0xe9 + int qemu_cfg_enabled(void); int qemu_cfg_dma_enabled(void); void qemu_preinit(void); |