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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: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <1423766494-26150-2-git-send-email-rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Radim Krčmář 2015-02-12 19:41:31 +01:00 committed by Paolo Bonzini
parent 1945606031
commit 03d2249ea6
1 changed files with 33 additions and 7 deletions
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40
arch/x86/kvm/lapic.c
View File

@ -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: