Re: [PATCH 1/2] LoongArch: KVM: Fix PC double advance in kernel MMIO read fast path

Tao Cui <[email protected]> Sat, 25 Jul 2026 11:38:20 +0800
Newsgroups dev.linux.lists.loongarch,org.kernel.vger.kvm,org.kernel.vger.linux-kernel,org.kernel.vger.stable
Message-ID <[email protected]>
From: Tao Cui <[email protected]>

> In the in-kernel MMIO read fast path of kvm_emu_mmio_read(),
> kvm_complete_mmio_read() already advances the guest PC via update_pc().
> The explicit update_pc() call right after it advances the PC a second
> time, so PC moves forward by 8 instead of 4 and the instruction
> following the MMIO read is silently skipped.

Good catch!
Reviewed-by: Tao Cui <[email protected]>