From 0d42522bdee70b9197be63dd76c9f6297cd1e832 Mon Sep 17 00:00:00 2001 From: Jinliang Zheng Date: Wed, 19 Apr 2023 10:19:25 +0800 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/20230419021924.1342184-1-alexjlzheng@tencent.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/i8259.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c index 4756bcb..8dec646 100644 --- a/arch/x86/kvm/i8259.c +++ b/arch/x86/kvm/i8259.c @@ -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); } -- 2.7.4