From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- arch/mips/jazz/reset.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 arch/mips/jazz/reset.c (limited to 'arch/mips/jazz/reset.c') diff --git a/arch/mips/jazz/reset.c b/arch/mips/jazz/reset.c new file mode 100644 index 000000000..052b01f5d --- /dev/null +++ b/arch/mips/jazz/reset.c @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Reset a Jazz machine. + * + * We don't trust the firmware so we do it the classic way by poking and + * stabbing at the keyboard controller ... + */ +#include +#include + +#define KBD_STAT_IBF 0x02 /* Keyboard input buffer full */ + +static void jazz_write_output(unsigned char val) +{ + int status; + + do { + status = jazz_kh->command; + } while (status & KBD_STAT_IBF); + jazz_kh->data = val; +} + +static void jazz_write_command(unsigned char val) +{ + int status; + + do { + status = jazz_kh->command; + } while (status & KBD_STAT_IBF); + jazz_kh->command = val; +} + +static unsigned char jazz_read_status(void) +{ + return jazz_kh->command; +} + +static inline void kb_wait(void) +{ + unsigned long start = jiffies; + unsigned long timeout = start + HZ/2; + + do { + if (! (jazz_read_status() & 0x02)) + return; + } while (time_before_eq(jiffies, timeout)); +} + +void jazz_machine_restart(char *command) +{ + while(1) { + kb_wait(); + jazz_write_command(0xd1); + kb_wait(); + jazz_write_output(0x00); + } +} -- cgit v1.3.1