KVM: x86: ioapic: Preserve read-only values in the redirection table (b200dded) · Commits · 戴 / test

According to 82093AA (IOAPIC) manual, Remote IRR and Delivery Status are read-only. QEMU implements the bits as RO in commit 479c2a1cb7fb ("ioapic: keep RO bits for IOAPIC entry"). Signed-off-by:

Nikita Leshenko <nikita.leshchenko@oracle.com> Reviewed-by:

Liran Alon <liran.alon@oracle.com> Signed-off-by:

Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by:

Wanpeng Li <wanpeng.li@hotmail.com> Reviewed-by:

Steve Rutherford <srutherford@google.com> Signed-off-by:

Radim Krčmář <rkrcmar@redhat.com>

arch/x86/kvm/ioapic.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -276,6 +276,7 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
		{
		unsigned index;
		bool mask_before, mask_after;
		int old_remote_irr, old_delivery_status;
		union kvm_ioapic_redirect_entry *e;

		switch (ioapic->ioregsel) {
		@@ -298,6 +299,9 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
		return;
		e = &ioapic->redirtbl[index];
		mask_before = e->fields.mask;
		/* Preserve read-only fields */
		old_remote_irr = e->fields.remote_irr;
		old_delivery_status = e->fields.delivery_status;
		if (ioapic->ioregsel & 1) {
		e->bits &= 0xffffffff;
		e->bits \|= (u64) val << 32;
		@@ -305,6 +309,8 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
		e->bits &= ~0xffffffffULL;
		e->bits \|= (u32) val;
		}
		e->fields.remote_irr = old_remote_irr;
		e->fields.delivery_status = old_delivery_status;

		/*
		* Some OSes (Linux, Xen) assume that Remote IRR bit will

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