3.16.7-ckt11 -stable review patch. If anyone has any objections, please let me know.
------------------
From: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
commit 261520dcfcba93ca5dfe671b88ffab038cd940c8 upstream.
If the I/O interrupt could not be written to the guest provided
area (e.g. access exception), a program exception was injected into the
guest but "inti" wasn't freed, therefore resulting in a memory leak.
In addition, the I/O interrupt wasn't reinjected. Therefore the dequeued
interrupt is lost.
This patch fixes the problem while cleaning up the function and making the
cc and rc logic easier to handle.
Signed-off-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
arch/s390/kvm/priv.c | 40 +++++++++++++++++++++++-----------------
1 file changed, 23 insertions(+), 17 deletions(-)
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 3d2e3b7c50db..a07965490779 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -228,18 +228,19 @@ static int handle_tpi(struct kvm_vcpu *vcpu)
struct kvm_s390_interrupt_info *inti;
unsigned long len;
u32 tpi_data[3];
- int cc, rc;
+ int rc;
u64 addr;
- rc = 0;
addr = kvm_s390_get_base_disp_s(vcpu);
if (addr & 3)
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
- cc = 0;
+
inti = kvm_s390_get_io_int(vcpu->kvm, vcpu->arch.sie_block->gcr[6], 0);
- if (!inti)
- goto no_interrupt;
- cc = 1;
+ if (!inti) {
+ kvm_s390_set_psw_cc(vcpu, 0);
+ return 0;
+ }
+
tpi_data[0] = inti->io.subchannel_id << 16 | inti->io.subchannel_nr;
tpi_data[1] = inti->io.io_int_parm;
tpi_data[2] = inti->io.io_int_word;
@@ -250,30 +251,35 @@ static int handle_tpi(struct kvm_vcpu *vcpu)
*/
len = sizeof(tpi_data) - 4;
rc = write_guest(vcpu, addr, &tpi_data, len);
- if (rc)
- return kvm_s390_inject_prog_cond(vcpu, rc);
+ if (rc) {
+ rc = kvm_s390_inject_prog_cond(vcpu, rc);
+ goto reinject_interrupt;
+ }
} else {
/*
* Store the three-word I/O interruption code into
* the appropriate lowcore area.
*/
len = sizeof(tpi_data);
- if (write_guest_lc(vcpu, __LC_SUBCHANNEL_ID, &tpi_data, len))
+ if (write_guest_lc(vcpu, __LC_SUBCHANNEL_ID, &tpi_data, len)) {
+ /* failed writes to the low core are not recoverable */
rc = -EFAULT;
+ goto reinject_interrupt;
+ }
}
+
+ /* irq was successfully handed to the guest */
+ kfree(inti);
+ kvm_s390_set_psw_cc(vcpu, 1);
+ return 0;
+reinject_interrupt:
/*
* If we encounter a problem storing the interruption code, the
* instruction is suppressed from the guest's view: reinject the
* interrupt.
*/
- if (!rc)
- kfree(inti);
- else
- kvm_s390_reinject_io_int(vcpu->kvm, inti);
-no_interrupt:
- /* Set condition code and we're done. */
- if (!rc)
- kvm_s390_set_psw_cc(vcpu, cc);
+ kvm_s390_reinject_io_int(vcpu->kvm, inti);
+ /* don't set the cc, a pgm irq was injected or we drop to user space */
return rc ? -EFAULT : 0;
}
--
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