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authorNikita Leshenko <nikita.leshchenko@oracle.com>2017-11-05 15:52:33 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2017-11-17 13:20:21 +0100
commitb200dded0a6974a3b69599832b2203483920ab25 (patch)
tree76d029dac724fd0a5d5a1ceae7e4a71642b18402 /arch
parenta8bfec2930525808c01f038825d1df3904638631 (diff)
downloadlinux-b200dded0a6974a3b69599832b2203483920ab25.tar.bz2
KVM: x86: ioapic: Preserve read-only values in the redirection table
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/ioapic.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
index 163d340ee5f8..4e822ad363f3 100644
--- a/arch/x86/kvm/ioapic.c
+++ b/arch/x86/kvm/ioapic.c
@@ -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