Commit 03d2249e authored by Radim Krčmář's avatar Radim Krčmář Committed by Paolo Bonzini
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KVM: x86: use MDA for interrupt matching 



In mixed modes, we musn't deliver xAPIC IPIs like x2APIC and vice versa.
Instead of preserving the information in apic_send_ipi(), we regain it
by converting all destinations into correct MDA in the slow path.
This allows easier reasoning about subsequent matching.

Our kvm_apic_broadcast() had an interesting design decision: it didn't
consider IOxAPIC 0xff as broadcast in x2APIC mode ...
everything worked because IOxAPIC can't set that in physical mode and
logical mode considered it as a message for first 8 VCPUs.
This patch interprets IOxAPIC 0xff as x2APIC broadcast.

Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
Message-Id: <1423766494-26150-2-git-send-email-rkrcmar@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 19456060

arch/x86/kvm/lapic.c

+33 −7
Original line number Diff line number Diff line
@@ -588,15 +588,23 @@ static void apic_set_tpr(struct kvm_lapic *apic, u32 tpr) 
	apic_update_ppr(apic);

}



static bool kvm_apic_broadcast(struct kvm_lapic *apic, u32 dest)

static bool kvm_apic_broadcast(struct kvm_lapic *apic, u32 mda)

{

	return dest == (apic_x2apic_mode(apic) ?

			X2APIC_BROADCAST : APIC_BROADCAST);

	if (apic_x2apic_mode(apic))

		return mda == X2APIC_BROADCAST;



	return GET_APIC_DEST_FIELD(mda) == APIC_BROADCAST;

}



static bool kvm_apic_match_physical_addr(struct kvm_lapic *apic, u32 dest)

static bool kvm_apic_match_physical_addr(struct kvm_lapic *apic, u32 mda)

{

	return kvm_apic_id(apic) == dest || kvm_apic_broadcast(apic, dest);

	if (kvm_apic_broadcast(apic, mda))

		return true;



	if (apic_x2apic_mode(apic))

		return mda == kvm_apic_id(apic);



	return mda == SET_APIC_DEST_FIELD(kvm_apic_id(apic));

}



static bool kvm_apic_match_logical_addr(struct kvm_lapic *apic, u32 mda)
@@ -613,6 +621,7 @@ static bool kvm_apic_match_logical_addr(struct kvm_lapic *apic, u32 mda) 
		       && (logical_id & mda & 0xffff) != 0;



	logical_id = GET_APIC_LOGICAL_ID(logical_id);

	mda = GET_APIC_DEST_FIELD(mda);



	switch (kvm_apic_get_reg(apic, APIC_DFR)) {

	case APIC_DFR_FLAT:
@@ -627,10 +636,27 @@ static bool kvm_apic_match_logical_addr(struct kvm_lapic *apic, u32 mda) 
	}

}



/* KVM APIC implementation has two quirks

 *  - dest always begins at 0 while xAPIC MDA has offset 24,

 *  - IOxAPIC messages have to be delivered (directly) to x2APIC.

 */

static u32 kvm_apic_mda(unsigned int dest_id, struct kvm_lapic *source,

                                              struct kvm_lapic *target)

{

	bool ipi = source != NULL;

	bool x2apic_mda = apic_x2apic_mode(ipi ? source : target);



	if (!ipi && dest_id == APIC_BROADCAST && x2apic_mda)

		return X2APIC_BROADCAST;



	return x2apic_mda ? dest_id : SET_APIC_DEST_FIELD(dest_id);

}



bool kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,

			   int short_hand, unsigned int dest, int dest_mode)

{

	struct kvm_lapic *target = vcpu->arch.apic;

	u32 mda = kvm_apic_mda(dest, source, target);



	apic_debug("target %p, source %p, dest 0x%x, "

		   "dest_mode 0x%x, short_hand 0x%x\n",
@@ -640,9 +666,9 @@ bool kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source, 
	switch (short_hand) {

	case APIC_DEST_NOSHORT:

		if (dest_mode == APIC_DEST_PHYSICAL)

			return kvm_apic_match_physical_addr(target, dest);

			return kvm_apic_match_physical_addr(target, mda);

		else

			return kvm_apic_match_logical_addr(target, dest);

			return kvm_apic_match_logical_addr(target, mda);

	case APIC_DEST_SELF:

		return target == source;

	case APIC_DEST_ALLINC:

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