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KVM: x86: Fix poll command 

According to the hardware manual, when the Poll command is issued, the
byte returned by the I/O read is 1 in Bit 7 when there is an interrupt,
and the highest priority binary code in Bits 2:0. The current pic
simulation code is not implemented strictly according to the above
expression.

Fix the implementation of pic_poll_read(), set Bit 7 when there is an
interrupt.

Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com>
Link: https://lore.kernel.org/r/20230419021924.1342184-1-alexjlzheng@tencent.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Jinliang Zheng 2023-04-19 10:19:25 +08:00 committed by Sean Christopherson
parent dee321977a
commit 0d42522bde
1 changed files with 3 additions and 0 deletions
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3
arch/x86/kvm/i8259.c
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@ -411,7 +411,10 @@ static u32 pic_poll_read(struct kvm_kpic_state *s, u32 addr1)
pic_clear_isr(s, ret);
if (addr1 >> 7 || ret != 2)
pic_update_irq(s->pics_state);
/* Bit 7 is 1, means there's an interrupt */
ret |= 0x80;
} else {
/* Bit 7 is 0, means there's no interrupt */
ret = 0x07;
pic_update_irq(s->pics_state);
}