This is a note to let you know that I've just added the patch titled
KVM: s390: fix handling of write errors in the tpi handler
to the 3.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-s390-fix-handling-of-write-errors-in-the-tpi-handler.patch
and it can be found in the queue-3.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 261520dcfcba93ca5dfe671b88ffab038cd940c8 Mon Sep 17 00:00:00 2001
From: David Hildenbrand <[email protected]>
Date: Wed, 4 Feb 2015 15:53:42 +0100
Subject: KVM: s390: fix handling of write errors in the tpi handler
From: David Hildenbrand <[email protected]>
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 <[email protected]>
Signed-off-by: Christian Borntraeger <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/s390/kvm/priv.c | 40 +++++++++++++++++++++++-----------------
1 file changed, 23 insertions(+), 17 deletions(-)
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -229,18 +229,19 @@ static int handle_tpi(struct kvm_vcpu *v
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;
@@ -251,30 +252,35 @@ static int handle_tpi(struct kvm_vcpu *v
*/
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;
}
Patches currently in stable-queue which might be from [email protected]
are
queue-3.19/kvm-s390-zero-out-current-vmdb-of-stsi-before-including-level3-data.patch
queue-3.19/kvm-s390-reinjection-of-irqs-can-fail-in-the-tpi-handler.patch
queue-3.19/kvm-s390-fix-get_all_floating_irqs.patch
queue-3.19/kvm-s390-fix-handling-of-write-errors-in-the-tpi-handler.patch
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