* [PATCH v3] KVM: s390: vsie: Avoid injecting machine check on signal
@ 2026-03-16 13:09 Christian Borntraeger
2026-03-16 13:13 ` Heiko Carstens
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Christian Borntraeger @ 2026-03-16 13:09 UTC (permalink / raw)
To: KVM
Cc: Christian Borntraeger, Janosch Frank, David Hildenbrand,
linux-s390, Thomas Huth, Claudio Imbrenda, Heiko Carstens,
Vasily Gorbik, Alexander Gordeev
The recent XFER_TO_GUEST_WORK change resulted in a situation, where the
vsie code would interpret a signal during work as a machine check during
SIE as both use the EINTR return code.
The exit_reason of the sie64a function has nothing to do with the
kvm_run exit_reason. Rename it and define a specific code for machine
checks instead of abusing -EINTR.
rename exit_reason into sie_return to avoid the naming conflict
and change the code flow in vsie.c to have a separate variable for rc
and sie_return.
Fixes: 2bd1337a1295e ("KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions")
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
---
v1->v2:
instead of a band-aid, make the machine check more direct
v2->v3:
avoid overloading the rc variable in vsie.c
arch/s390/include/asm/kvm_host.h | 3 +++
arch/s390/include/asm/stacktrace.h | 2 +-
arch/s390/kernel/asm-offsets.c | 2 +-
arch/s390/kernel/entry.S | 4 ++--
arch/s390/kernel/nmi.c | 4 ++--
arch/s390/kvm/kvm-s390.c | 15 ++++++++-------
arch/s390/kvm/vsie.c | 7 +++++--
7 files changed, 22 insertions(+), 15 deletions(-)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 64a50f0862aa..3039c88daa63 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -710,6 +710,9 @@ void kvm_arch_crypto_clear_masks(struct kvm *kvm);
void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
unsigned long *aqm, unsigned long *adm);
+#define SIE64_RETURN_NORMAL 0
+#define SIE64_RETURN_MCCK 1
+
int __sie64a(phys_addr_t sie_block_phys, struct kvm_s390_sie_block *sie_block, u64 *rsa,
unsigned long gasce);
diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h
index c9ae680a28af..ac3606c3babe 100644
--- a/arch/s390/include/asm/stacktrace.h
+++ b/arch/s390/include/asm/stacktrace.h
@@ -62,7 +62,7 @@ struct stack_frame {
struct {
unsigned long sie_control_block;
unsigned long sie_savearea;
- unsigned long sie_reason;
+ unsigned long sie_return;
unsigned long sie_flags;
unsigned long sie_control_block_phys;
unsigned long sie_guest_asce;
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index e1a5b5b54e4f..fbd26f3e9f96 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -63,7 +63,7 @@ int main(void)
OFFSET(__SF_EMPTY, stack_frame, empty[0]);
OFFSET(__SF_SIE_CONTROL, stack_frame, sie_control_block);
OFFSET(__SF_SIE_SAVEAREA, stack_frame, sie_savearea);
- OFFSET(__SF_SIE_REASON, stack_frame, sie_reason);
+ OFFSET(__SF_SIE_RETURN, stack_frame, sie_return);
OFFSET(__SF_SIE_FLAGS, stack_frame, sie_flags);
OFFSET(__SF_SIE_CONTROL_PHYS, stack_frame, sie_control_block_phys);
OFFSET(__SF_SIE_GUEST_ASCE, stack_frame, sie_guest_asce);
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 4873fe9d891b..5817cb47b2d0 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -200,7 +200,7 @@ SYM_FUNC_START(__sie64a)
stg %r3,__SF_SIE_CONTROL(%r15) # ...and virtual addresses
stg %r4,__SF_SIE_SAVEAREA(%r15) # save guest register save area
stg %r5,__SF_SIE_GUEST_ASCE(%r15) # save guest asce
- xc __SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0
+ xc __SF_SIE_RETURN(8,%r15),__SF_SIE_RETURN(%r15) # return code = 0
mvc __SF_SIE_FLAGS(8,%r15),__TI_flags(%r14) # copy thread flags
lmg %r0,%r13,0(%r4) # load guest gprs 0-13
mvi __TI_sie(%r14),1
@@ -237,7 +237,7 @@ SYM_INNER_LABEL(sie_exit, SYM_L_GLOBAL)
xgr %r4,%r4
xgr %r5,%r5
lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers
- lg %r2,__SF_SIE_REASON(%r15) # return exit reason code
+ lg %r2,__SF_SIE_RETURN(%r15) # return sie return code
BR_EX %r14
SYM_FUNC_END(__sie64a)
EXPORT_SYMBOL(__sie64a)
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index a55abbf65333..fc1f775e4517 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -487,8 +487,8 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);
if (test_cpu_flag(CIF_MCCK_GUEST) &&
(mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {
- /* Set exit reason code for host's later handling */
- *((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;
+ /* Set sie return code for host's later handling */
+ *((long *)(regs->gprs[15] + __SF_SIE_RETURN)) = SIE64_RETURN_MCCK;
}
clear_cpu_flag(CIF_MCCK_GUEST);
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 1668580008c6..b93722b57d1c 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -4617,7 +4617,7 @@ static int vcpu_post_run_handle_fault(struct kvm_vcpu *vcpu)
return 0;
}
-static int vcpu_post_run(struct kvm_vcpu *vcpu, int exit_reason)
+static int vcpu_post_run(struct kvm_vcpu *vcpu, int sie_return)
{
struct mcck_volatile_info *mcck_info;
struct sie_page *sie_page;
@@ -4633,13 +4633,14 @@ static int vcpu_post_run(struct kvm_vcpu *vcpu, int exit_reason)
vcpu->run->s.regs.gprs[14] = vcpu->arch.sie_block->gg14;
vcpu->run->s.regs.gprs[15] = vcpu->arch.sie_block->gg15;
- if (exit_reason == -EINTR) {
+ if (sie_return == SIE64_RETURN_MCCK) {
sie_page = container_of(vcpu->arch.sie_block,
struct sie_page, sie_block);
mcck_info = &sie_page->mcck_info;
kvm_s390_reinject_machine_check(vcpu, mcck_info);
return 0;
}
+ WARN_ON(sie_return != SIE64_RETURN_NORMAL);
if (vcpu->arch.sie_block->icptcode > 0) {
rc = kvm_handle_sie_intercept(vcpu);
@@ -4678,7 +4679,7 @@ int noinstr kvm_s390_enter_exit_sie(struct kvm_s390_sie_block *scb,
#define PSW_INT_MASK (PSW_MASK_EXT | PSW_MASK_IO | PSW_MASK_MCHECK)
static int __vcpu_run(struct kvm_vcpu *vcpu)
{
- int rc, exit_reason;
+ int rc, sie_return;
struct sie_page *sie_page = (struct sie_page *)vcpu->arch.sie_block;
/*
@@ -4718,9 +4719,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
guest_timing_enter_irqoff();
__disable_cpu_timer_accounting(vcpu);
- exit_reason = kvm_s390_enter_exit_sie(vcpu->arch.sie_block,
- vcpu->run->s.regs.gprs,
- vcpu->arch.gmap->asce.val);
+ sie_return = kvm_s390_enter_exit_sie(vcpu->arch.sie_block,
+ vcpu->run->s.regs.gprs,
+ vcpu->arch.gmap->asce.val);
__enable_cpu_timer_accounting(vcpu);
guest_timing_exit_irqoff();
@@ -4743,7 +4744,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
}
kvm_vcpu_srcu_read_lock(vcpu);
- rc = vcpu_post_run(vcpu, exit_reason);
+ rc = vcpu_post_run(vcpu, sie_return);
if (rc || guestdbg_exit_pending(vcpu)) {
kvm_vcpu_srcu_read_unlock(vcpu);
break;
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index c0d36afd4023..42c53134e0b8 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -1123,6 +1123,7 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struc
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
int guest_bp_isolation;
+ int sie_return = SIE64_RETURN_NORMAL;
int rc = 0;
handle_last_fault(vcpu, vsie_page, sg);
@@ -1163,7 +1164,7 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struc
goto xfer_to_guest_mode_check;
}
guest_timing_enter_irqoff();
- rc = kvm_s390_enter_exit_sie(scb_s, vcpu->run->s.regs.gprs, sg->asce.val);
+ sie_return = kvm_s390_enter_exit_sie(scb_s, vcpu->run->s.regs.gprs, sg->asce.val);
guest_timing_exit_irqoff();
local_irq_enable();
}
@@ -1178,11 +1179,13 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struc
kvm_vcpu_srcu_read_lock(vcpu);
- if (rc == -EINTR) {
+ if (sie_return == SIE64_RETURN_MCCK) {
kvm_s390_reinject_machine_check(vcpu, &vsie_page->mcck_info);
return 0;
}
+ WARN_ON(sie_return != SIE64_RETURN_NORMAL);
+
if (rc > 0)
rc = 0; /* we could still have an icpt */
else if (current->thread.gmap_int_code)
--
2.53.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v3] KVM: s390: vsie: Avoid injecting machine check on signal
2026-03-16 13:09 [PATCH v3] KVM: s390: vsie: Avoid injecting machine check on signal Christian Borntraeger
@ 2026-03-16 13:13 ` Heiko Carstens
2026-03-16 13:42 ` Claudio Imbrenda
2026-03-16 13:57 ` Janosch Frank
2 siblings, 0 replies; 6+ messages in thread
From: Heiko Carstens @ 2026-03-16 13:13 UTC (permalink / raw)
To: Christian Borntraeger
Cc: KVM, Janosch Frank, David Hildenbrand, linux-s390, Thomas Huth,
Claudio Imbrenda, Vasily Gorbik, Alexander Gordeev
On Mon, Mar 16, 2026 at 02:09:47PM +0100, Christian Borntraeger wrote:
> The recent XFER_TO_GUEST_WORK change resulted in a situation, where the
> vsie code would interpret a signal during work as a machine check during
> SIE as both use the EINTR return code.
> The exit_reason of the sie64a function has nothing to do with the
> kvm_run exit_reason. Rename it and define a specific code for machine
> checks instead of abusing -EINTR.
> rename exit_reason into sie_return to avoid the naming conflict
> and change the code flow in vsie.c to have a separate variable for rc
> and sie_return.
>
> Fixes: 2bd1337a1295e ("KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions")
> Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> ---
> v1->v2:
> instead of a band-aid, make the machine check more direct
> v2->v3:
> avoid overloading the rc variable in vsie.c
>
> arch/s390/include/asm/kvm_host.h | 3 +++
> arch/s390/include/asm/stacktrace.h | 2 +-
> arch/s390/kernel/asm-offsets.c | 2 +-
> arch/s390/kernel/entry.S | 4 ++--
> arch/s390/kernel/nmi.c | 4 ++--
> arch/s390/kvm/kvm-s390.c | 15 ++++++++-------
> arch/s390/kvm/vsie.c | 7 +++++--
> 7 files changed, 22 insertions(+), 15 deletions(-)
...
> diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
> index c0d36afd4023..42c53134e0b8 100644
> --- a/arch/s390/kvm/vsie.c
> +++ b/arch/s390/kvm/vsie.c
> @@ -1123,6 +1123,7 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struc
> struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
> struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
> int guest_bp_isolation;
> + int sie_return = SIE64_RETURN_NORMAL;
> int rc = 0;
Move that one line up to keep the reverse x-mas style?
> + WARN_ON(sie_return != SIE64_RETURN_NORMAL);
And as written in the previous version: both should be WARN_ON_ONCE() I guess.
Anyway:
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] KVM: s390: vsie: Avoid injecting machine check on signal
2026-03-16 13:09 [PATCH v3] KVM: s390: vsie: Avoid injecting machine check on signal Christian Borntraeger
2026-03-16 13:13 ` Heiko Carstens
@ 2026-03-16 13:42 ` Claudio Imbrenda
2026-03-16 13:57 ` Janosch Frank
2 siblings, 0 replies; 6+ messages in thread
From: Claudio Imbrenda @ 2026-03-16 13:42 UTC (permalink / raw)
To: Christian Borntraeger
Cc: KVM, Janosch Frank, David Hildenbrand, linux-s390, Thomas Huth,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev
On Mon, 16 Mar 2026 14:09:47 +0100
Christian Borntraeger <borntraeger@linux.ibm.com> wrote:
> The recent XFER_TO_GUEST_WORK change resulted in a situation, where the
> vsie code would interpret a signal during work as a machine check during
> SIE as both use the EINTR return code.
> The exit_reason of the sie64a function has nothing to do with the
> kvm_run exit_reason. Rename it and define a specific code for machine
> checks instead of abusing -EINTR.
> rename exit_reason into sie_return to avoid the naming conflict
> and change the code flow in vsie.c to have a separate variable for rc
> and sie_return.
>
> Fixes: 2bd1337a1295e ("KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions")
> Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
With Heiko's comments addresssed:
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
> v1->v2:
> instead of a band-aid, make the machine check more direct
> v2->v3:
> avoid overloading the rc variable in vsie.c
>
> arch/s390/include/asm/kvm_host.h | 3 +++
> arch/s390/include/asm/stacktrace.h | 2 +-
> arch/s390/kernel/asm-offsets.c | 2 +-
> arch/s390/kernel/entry.S | 4 ++--
> arch/s390/kernel/nmi.c | 4 ++--
> arch/s390/kvm/kvm-s390.c | 15 ++++++++-------
> arch/s390/kvm/vsie.c | 7 +++++--
> 7 files changed, 22 insertions(+), 15 deletions(-)
>
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 64a50f0862aa..3039c88daa63 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -710,6 +710,9 @@ void kvm_arch_crypto_clear_masks(struct kvm *kvm);
> void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
> unsigned long *aqm, unsigned long *adm);
>
> +#define SIE64_RETURN_NORMAL 0
> +#define SIE64_RETURN_MCCK 1
> +
> int __sie64a(phys_addr_t sie_block_phys, struct kvm_s390_sie_block *sie_block, u64 *rsa,
> unsigned long gasce);
>
> diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h
> index c9ae680a28af..ac3606c3babe 100644
> --- a/arch/s390/include/asm/stacktrace.h
> +++ b/arch/s390/include/asm/stacktrace.h
> @@ -62,7 +62,7 @@ struct stack_frame {
> struct {
> unsigned long sie_control_block;
> unsigned long sie_savearea;
> - unsigned long sie_reason;
> + unsigned long sie_return;
> unsigned long sie_flags;
> unsigned long sie_control_block_phys;
> unsigned long sie_guest_asce;
> diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
> index e1a5b5b54e4f..fbd26f3e9f96 100644
> --- a/arch/s390/kernel/asm-offsets.c
> +++ b/arch/s390/kernel/asm-offsets.c
> @@ -63,7 +63,7 @@ int main(void)
> OFFSET(__SF_EMPTY, stack_frame, empty[0]);
> OFFSET(__SF_SIE_CONTROL, stack_frame, sie_control_block);
> OFFSET(__SF_SIE_SAVEAREA, stack_frame, sie_savearea);
> - OFFSET(__SF_SIE_REASON, stack_frame, sie_reason);
> + OFFSET(__SF_SIE_RETURN, stack_frame, sie_return);
> OFFSET(__SF_SIE_FLAGS, stack_frame, sie_flags);
> OFFSET(__SF_SIE_CONTROL_PHYS, stack_frame, sie_control_block_phys);
> OFFSET(__SF_SIE_GUEST_ASCE, stack_frame, sie_guest_asce);
> diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
> index 4873fe9d891b..5817cb47b2d0 100644
> --- a/arch/s390/kernel/entry.S
> +++ b/arch/s390/kernel/entry.S
> @@ -200,7 +200,7 @@ SYM_FUNC_START(__sie64a)
> stg %r3,__SF_SIE_CONTROL(%r15) # ...and virtual addresses
> stg %r4,__SF_SIE_SAVEAREA(%r15) # save guest register save area
> stg %r5,__SF_SIE_GUEST_ASCE(%r15) # save guest asce
> - xc __SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0
> + xc __SF_SIE_RETURN(8,%r15),__SF_SIE_RETURN(%r15) # return code = 0
> mvc __SF_SIE_FLAGS(8,%r15),__TI_flags(%r14) # copy thread flags
> lmg %r0,%r13,0(%r4) # load guest gprs 0-13
> mvi __TI_sie(%r14),1
> @@ -237,7 +237,7 @@ SYM_INNER_LABEL(sie_exit, SYM_L_GLOBAL)
> xgr %r4,%r4
> xgr %r5,%r5
> lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers
> - lg %r2,__SF_SIE_REASON(%r15) # return exit reason code
> + lg %r2,__SF_SIE_RETURN(%r15) # return sie return code
> BR_EX %r14
> SYM_FUNC_END(__sie64a)
> EXPORT_SYMBOL(__sie64a)
> diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
> index a55abbf65333..fc1f775e4517 100644
> --- a/arch/s390/kernel/nmi.c
> +++ b/arch/s390/kernel/nmi.c
> @@ -487,8 +487,8 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
> mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);
> if (test_cpu_flag(CIF_MCCK_GUEST) &&
> (mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {
> - /* Set exit reason code for host's later handling */
> - *((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;
> + /* Set sie return code for host's later handling */
> + *((long *)(regs->gprs[15] + __SF_SIE_RETURN)) = SIE64_RETURN_MCCK;
> }
> clear_cpu_flag(CIF_MCCK_GUEST);
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 1668580008c6..b93722b57d1c 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -4617,7 +4617,7 @@ static int vcpu_post_run_handle_fault(struct kvm_vcpu *vcpu)
> return 0;
> }
>
> -static int vcpu_post_run(struct kvm_vcpu *vcpu, int exit_reason)
> +static int vcpu_post_run(struct kvm_vcpu *vcpu, int sie_return)
> {
> struct mcck_volatile_info *mcck_info;
> struct sie_page *sie_page;
> @@ -4633,13 +4633,14 @@ static int vcpu_post_run(struct kvm_vcpu *vcpu, int exit_reason)
> vcpu->run->s.regs.gprs[14] = vcpu->arch.sie_block->gg14;
> vcpu->run->s.regs.gprs[15] = vcpu->arch.sie_block->gg15;
>
> - if (exit_reason == -EINTR) {
> + if (sie_return == SIE64_RETURN_MCCK) {
> sie_page = container_of(vcpu->arch.sie_block,
> struct sie_page, sie_block);
> mcck_info = &sie_page->mcck_info;
> kvm_s390_reinject_machine_check(vcpu, mcck_info);
> return 0;
> }
> + WARN_ON(sie_return != SIE64_RETURN_NORMAL);
>
> if (vcpu->arch.sie_block->icptcode > 0) {
> rc = kvm_handle_sie_intercept(vcpu);
> @@ -4678,7 +4679,7 @@ int noinstr kvm_s390_enter_exit_sie(struct kvm_s390_sie_block *scb,
> #define PSW_INT_MASK (PSW_MASK_EXT | PSW_MASK_IO | PSW_MASK_MCHECK)
> static int __vcpu_run(struct kvm_vcpu *vcpu)
> {
> - int rc, exit_reason;
> + int rc, sie_return;
> struct sie_page *sie_page = (struct sie_page *)vcpu->arch.sie_block;
>
> /*
> @@ -4718,9 +4719,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
> guest_timing_enter_irqoff();
> __disable_cpu_timer_accounting(vcpu);
>
> - exit_reason = kvm_s390_enter_exit_sie(vcpu->arch.sie_block,
> - vcpu->run->s.regs.gprs,
> - vcpu->arch.gmap->asce.val);
> + sie_return = kvm_s390_enter_exit_sie(vcpu->arch.sie_block,
> + vcpu->run->s.regs.gprs,
> + vcpu->arch.gmap->asce.val);
>
> __enable_cpu_timer_accounting(vcpu);
> guest_timing_exit_irqoff();
> @@ -4743,7 +4744,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
> }
> kvm_vcpu_srcu_read_lock(vcpu);
>
> - rc = vcpu_post_run(vcpu, exit_reason);
> + rc = vcpu_post_run(vcpu, sie_return);
> if (rc || guestdbg_exit_pending(vcpu)) {
> kvm_vcpu_srcu_read_unlock(vcpu);
> break;
> diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
> index c0d36afd4023..42c53134e0b8 100644
> --- a/arch/s390/kvm/vsie.c
> +++ b/arch/s390/kvm/vsie.c
> @@ -1123,6 +1123,7 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struc
> struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
> struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
> int guest_bp_isolation;
> + int sie_return = SIE64_RETURN_NORMAL;
> int rc = 0;
>
> handle_last_fault(vcpu, vsie_page, sg);
> @@ -1163,7 +1164,7 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struc
> goto xfer_to_guest_mode_check;
> }
> guest_timing_enter_irqoff();
> - rc = kvm_s390_enter_exit_sie(scb_s, vcpu->run->s.regs.gprs, sg->asce.val);
> + sie_return = kvm_s390_enter_exit_sie(scb_s, vcpu->run->s.regs.gprs, sg->asce.val);
> guest_timing_exit_irqoff();
> local_irq_enable();
> }
> @@ -1178,11 +1179,13 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struc
>
> kvm_vcpu_srcu_read_lock(vcpu);
>
> - if (rc == -EINTR) {
> + if (sie_return == SIE64_RETURN_MCCK) {
> kvm_s390_reinject_machine_check(vcpu, &vsie_page->mcck_info);
> return 0;
> }
>
> + WARN_ON(sie_return != SIE64_RETURN_NORMAL);
> +
> if (rc > 0)
> rc = 0; /* we could still have an icpt */
> else if (current->thread.gmap_int_code)
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] KVM: s390: vsie: Avoid injecting machine check on signal
2026-03-16 13:09 [PATCH v3] KVM: s390: vsie: Avoid injecting machine check on signal Christian Borntraeger
2026-03-16 13:13 ` Heiko Carstens
2026-03-16 13:42 ` Claudio Imbrenda
@ 2026-03-16 13:57 ` Janosch Frank
2026-03-16 14:47 ` Christian Borntraeger
2 siblings, 1 reply; 6+ messages in thread
From: Janosch Frank @ 2026-03-16 13:57 UTC (permalink / raw)
To: Christian Borntraeger, KVM
Cc: David Hildenbrand, linux-s390, Thomas Huth, Claudio Imbrenda,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev
On 3/16/26 14:09, Christian Borntraeger wrote:
> The recent XFER_TO_GUEST_WORK change resulted in a situation, where the
> vsie code would interpret a signal during work as a machine check during
> SIE as both use the EINTR return code.
> The exit_reason of the sie64a function has nothing to do with the
> kvm_run exit_reason. Rename it and define a specific code for machine
> checks instead of abusing -EINTR.
> rename exit_reason into sie_return to avoid the naming conflict
> and change the code flow in vsie.c to have a separate variable for rc
> and sie_return.
>
> Fixes: 2bd1337a1295e ("KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions")
> Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> ---
> v1->v2:
> instead of a band-aid, make the machine check more direct
> v2->v3:
> avoid overloading the rc variable in vsie.c
>
> arch/s390/include/asm/kvm_host.h | 3 +++
> arch/s390/include/asm/stacktrace.h | 2 +-
> arch/s390/kernel/asm-offsets.c | 2 +-
> arch/s390/kernel/entry.S | 4 ++--
> arch/s390/kernel/nmi.c | 4 ++--
> arch/s390/kvm/kvm-s390.c | 15 ++++++++-------
> arch/s390/kvm/vsie.c | 7 +++++--
> 7 files changed, 22 insertions(+), 15 deletions(-)
>
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 64a50f0862aa..3039c88daa63 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -710,6 +710,9 @@ void kvm_arch_crypto_clear_masks(struct kvm *kvm);
> void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
> unsigned long *aqm, unsigned long *adm);
>
> +#define SIE64_RETURN_NORMAL 0
> +#define SIE64_RETURN_MCCK 1
> +
> int __sie64a(phys_addr_t sie_block_phys, struct kvm_s390_sie_block *sie_block, u64 *rsa,
> unsigned long gasce);
>
> diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h
> index c9ae680a28af..ac3606c3babe 100644
> --- a/arch/s390/include/asm/stacktrace.h
> +++ b/arch/s390/include/asm/stacktrace.h
> @@ -62,7 +62,7 @@ struct stack_frame {
> struct {
> unsigned long sie_control_block;
> unsigned long sie_savearea;
> - unsigned long sie_reason;
> + unsigned long sie_return;
> unsigned long sie_flags;
> unsigned long sie_control_block_phys;
> unsigned long sie_guest_asce;
> diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
> index e1a5b5b54e4f..fbd26f3e9f96 100644
> --- a/arch/s390/kernel/asm-offsets.c
> +++ b/arch/s390/kernel/asm-offsets.c
> @@ -63,7 +63,7 @@ int main(void)
> OFFSET(__SF_EMPTY, stack_frame, empty[0]);
> OFFSET(__SF_SIE_CONTROL, stack_frame, sie_control_block);
> OFFSET(__SF_SIE_SAVEAREA, stack_frame, sie_savearea);
> - OFFSET(__SF_SIE_REASON, stack_frame, sie_reason);
> + OFFSET(__SF_SIE_RETURN, stack_frame, sie_return);
> OFFSET(__SF_SIE_FLAGS, stack_frame, sie_flags);
> OFFSET(__SF_SIE_CONTROL_PHYS, stack_frame, sie_control_block_phys);
> OFFSET(__SF_SIE_GUEST_ASCE, stack_frame, sie_guest_asce);
> diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
> index 4873fe9d891b..5817cb47b2d0 100644
> --- a/arch/s390/kernel/entry.S
> +++ b/arch/s390/kernel/entry.S
> @@ -200,7 +200,7 @@ SYM_FUNC_START(__sie64a)
> stg %r3,__SF_SIE_CONTROL(%r15) # ...and virtual addresses
> stg %r4,__SF_SIE_SAVEAREA(%r15) # save guest register save area
> stg %r5,__SF_SIE_GUEST_ASCE(%r15) # save guest asce
> - xc __SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0
> + xc __SF_SIE_RETURN(8,%r15),__SF_SIE_RETURN(%r15) # return code = 0
> mvc __SF_SIE_FLAGS(8,%r15),__TI_flags(%r14) # copy thread flags
> lmg %r0,%r13,0(%r4) # load guest gprs 0-13
> mvi __TI_sie(%r14),1
> @@ -237,7 +237,7 @@ SYM_INNER_LABEL(sie_exit, SYM_L_GLOBAL)
> xgr %r4,%r4
> xgr %r5,%r5
> lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers
> - lg %r2,__SF_SIE_REASON(%r15) # return exit reason code
> + lg %r2,__SF_SIE_RETURN(%r15) # return sie return code
> BR_EX %r14
> SYM_FUNC_END(__sie64a)
> EXPORT_SYMBOL(__sie64a)
> diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
> index a55abbf65333..fc1f775e4517 100644
> --- a/arch/s390/kernel/nmi.c
> +++ b/arch/s390/kernel/nmi.c
> @@ -487,8 +487,8 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
> mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);
> if (test_cpu_flag(CIF_MCCK_GUEST) &&
> (mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {
> - /* Set exit reason code for host's later handling */
> - *((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;
> + /* Set sie return code for host's later handling */
> + *((long *)(regs->gprs[15] + __SF_SIE_RETURN)) = SIE64_RETURN_MCCK;
We don't need to cast this to long anymore, do we?
Since sie_return is ulong, and we if we stay with positive numbers ulong
would make the most sense.
Although I'd prefer a cast to stack_frame but I'm unsure if that would
make it more readable if we stay with a one line change.
Rest looks good to me
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] KVM: s390: vsie: Avoid injecting machine check on signal
2026-03-16 13:57 ` Janosch Frank
@ 2026-03-16 14:47 ` Christian Borntraeger
2026-03-16 15:11 ` Janosch Frank
0 siblings, 1 reply; 6+ messages in thread
From: Christian Borntraeger @ 2026-03-16 14:47 UTC (permalink / raw)
To: Janosch Frank, KVM
Cc: David Hildenbrand, linux-s390, Thomas Huth, Claudio Imbrenda,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev
Am 16.03.26 um 14:57 schrieb Janosch Frank:
> On 3/16/26 14:09, Christian Borntraeger wrote:
>> The recent XFER_TO_GUEST_WORK change resulted in a situation, where the
>> vsie code would interpret a signal during work as a machine check during
>> SIE as both use the EINTR return code.
>> The exit_reason of the sie64a function has nothing to do with the
>> kvm_run exit_reason. Rename it and define a specific code for machine
>> checks instead of abusing -EINTR.
>> rename exit_reason into sie_return to avoid the naming conflict
>> and change the code flow in vsie.c to have a separate variable for rc
>> and sie_return.
>>
>> Fixes: 2bd1337a1295e ("KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions")
>> Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
>> ---
>> v1->v2:
>> instead of a band-aid, make the machine check more direct
>> v2->v3:
>> avoid overloading the rc variable in vsie.c
>>
>> arch/s390/include/asm/kvm_host.h | 3 +++
>> arch/s390/include/asm/stacktrace.h | 2 +-
>> arch/s390/kernel/asm-offsets.c | 2 +-
>> arch/s390/kernel/entry.S | 4 ++--
>> arch/s390/kernel/nmi.c | 4 ++--
>> arch/s390/kvm/kvm-s390.c | 15 ++++++++-------
>> arch/s390/kvm/vsie.c | 7 +++++--
>> 7 files changed, 22 insertions(+), 15 deletions(-)
>>
>> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
>> index 64a50f0862aa..3039c88daa63 100644
>> --- a/arch/s390/include/asm/kvm_host.h
>> +++ b/arch/s390/include/asm/kvm_host.h
>> @@ -710,6 +710,9 @@ void kvm_arch_crypto_clear_masks(struct kvm *kvm);
>> void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
>> unsigned long *aqm, unsigned long *adm);
>> +#define SIE64_RETURN_NORMAL 0
>> +#define SIE64_RETURN_MCCK 1
>> +
>> int __sie64a(phys_addr_t sie_block_phys, struct kvm_s390_sie_block *sie_block, u64 *rsa,
>> unsigned long gasce);
>> diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h
>> index c9ae680a28af..ac3606c3babe 100644
>> --- a/arch/s390/include/asm/stacktrace.h
>> +++ b/arch/s390/include/asm/stacktrace.h
>> @@ -62,7 +62,7 @@ struct stack_frame {
>> struct {
>> unsigned long sie_control_block;
>> unsigned long sie_savearea;
>> - unsigned long sie_reason;
>> + unsigned long sie_return;
>> unsigned long sie_flags;
>> unsigned long sie_control_block_phys;
>> unsigned long sie_guest_asce;
>> diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
>> index e1a5b5b54e4f..fbd26f3e9f96 100644
>> --- a/arch/s390/kernel/asm-offsets.c
>> +++ b/arch/s390/kernel/asm-offsets.c
>> @@ -63,7 +63,7 @@ int main(void)
>> OFFSET(__SF_EMPTY, stack_frame, empty[0]);
>> OFFSET(__SF_SIE_CONTROL, stack_frame, sie_control_block);
>> OFFSET(__SF_SIE_SAVEAREA, stack_frame, sie_savearea);
>> - OFFSET(__SF_SIE_REASON, stack_frame, sie_reason);
>> + OFFSET(__SF_SIE_RETURN, stack_frame, sie_return);
>> OFFSET(__SF_SIE_FLAGS, stack_frame, sie_flags);
>> OFFSET(__SF_SIE_CONTROL_PHYS, stack_frame, sie_control_block_phys);
>> OFFSET(__SF_SIE_GUEST_ASCE, stack_frame, sie_guest_asce);
>> diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
>> index 4873fe9d891b..5817cb47b2d0 100644
>> --- a/arch/s390/kernel/entry.S
>> +++ b/arch/s390/kernel/entry.S
>> @@ -200,7 +200,7 @@ SYM_FUNC_START(__sie64a)
>> stg %r3,__SF_SIE_CONTROL(%r15) # ...and virtual addresses
>> stg %r4,__SF_SIE_SAVEAREA(%r15) # save guest register save area
>> stg %r5,__SF_SIE_GUEST_ASCE(%r15) # save guest asce
>> - xc __SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0
>> + xc __SF_SIE_RETURN(8,%r15),__SF_SIE_RETURN(%r15) # return code = 0
>> mvc __SF_SIE_FLAGS(8,%r15),__TI_flags(%r14) # copy thread flags
>> lmg %r0,%r13,0(%r4) # load guest gprs 0-13
>> mvi __TI_sie(%r14),1
>> @@ -237,7 +237,7 @@ SYM_INNER_LABEL(sie_exit, SYM_L_GLOBAL)
>> xgr %r4,%r4
>> xgr %r5,%r5
>> lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers
>> - lg %r2,__SF_SIE_REASON(%r15) # return exit reason code
>> + lg %r2,__SF_SIE_RETURN(%r15) # return sie return code
>> BR_EX %r14
>> SYM_FUNC_END(__sie64a)
>> EXPORT_SYMBOL(__sie64a)
>> diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
>> index a55abbf65333..fc1f775e4517 100644
>> --- a/arch/s390/kernel/nmi.c
>> +++ b/arch/s390/kernel/nmi.c
>> @@ -487,8 +487,8 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
>> mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);
>> if (test_cpu_flag(CIF_MCCK_GUEST) &&
>> (mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {
>> - /* Set exit reason code for host's later handling */
>> - *((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;
>> + /* Set sie return code for host's later handling */
>> + *((long *)(regs->gprs[15] + __SF_SIE_RETURN)) = SIE64_RETURN_MCCK;
>
> We don't need to cast this to long anymore, do we?
> Since sie_return is ulong, and we if we stay with positive numbers ulong would make the most sense.
>
> Although I'd prefer a cast to stack_frame but I'm unsure if that would make it more readable if we stay with a one line change.
something like
- *((long *)(regs->gprs[15] + __SF_SIE_RETURN)) = SIE64_RETURN_MCCK;
+ ((struct stack_frame *) regs->gprs[15])->sie_return = SIE64_RETURN_MCCK;
What do you think?
This reminds me that I should probably also make the local variable in vsie.c unsigned long instead of int.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] KVM: s390: vsie: Avoid injecting machine check on signal
2026-03-16 14:47 ` Christian Borntraeger
@ 2026-03-16 15:11 ` Janosch Frank
0 siblings, 0 replies; 6+ messages in thread
From: Janosch Frank @ 2026-03-16 15:11 UTC (permalink / raw)
To: Christian Borntraeger, KVM
Cc: David Hildenbrand, linux-s390, Thomas Huth, Claudio Imbrenda,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev
On 3/16/26 15:47, Christian Borntraeger wrote:
>
>
> Am 16.03.26 um 14:57 schrieb Janosch Frank:
>> On 3/16/26 14:09, Christian Borntraeger wrote:
>>> The recent XFER_TO_GUEST_WORK change resulted in a situation, where the
>>> vsie code would interpret a signal during work as a machine check during
>>> SIE as both use the EINTR return code.
>>> The exit_reason of the sie64a function has nothing to do with the
>>> kvm_run exit_reason. Rename it and define a specific code for machine
>>> checks instead of abusing -EINTR.
>>> rename exit_reason into sie_return to avoid the naming conflict
>>> and change the code flow in vsie.c to have a separate variable for rc
>>> and sie_return.
>>>
>>> Fixes: 2bd1337a1295e ("KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions")
>>> Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
>>> ---
>>> v1->v2:
>>> instead of a band-aid, make the machine check more direct
>>> v2->v3:
>>> avoid overloading the rc variable in vsie.c
>>>
>>> arch/s390/include/asm/kvm_host.h | 3 +++
>>> arch/s390/include/asm/stacktrace.h | 2 +-
>>> arch/s390/kernel/asm-offsets.c | 2 +-
>>> arch/s390/kernel/entry.S | 4 ++--
>>> arch/s390/kernel/nmi.c | 4 ++--
>>> arch/s390/kvm/kvm-s390.c | 15 ++++++++-------
>>> arch/s390/kvm/vsie.c | 7 +++++--
>>> 7 files changed, 22 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
>>> index 64a50f0862aa..3039c88daa63 100644
>>> --- a/arch/s390/include/asm/kvm_host.h
>>> +++ b/arch/s390/include/asm/kvm_host.h
>>> @@ -710,6 +710,9 @@ void kvm_arch_crypto_clear_masks(struct kvm *kvm);
>>> void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
>>> unsigned long *aqm, unsigned long *adm);
>>> +#define SIE64_RETURN_NORMAL 0
>>> +#define SIE64_RETURN_MCCK 1
>>> +
>>> int __sie64a(phys_addr_t sie_block_phys, struct kvm_s390_sie_block *sie_block, u64 *rsa,
>>> unsigned long gasce);
>>> diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h
>>> index c9ae680a28af..ac3606c3babe 100644
>>> --- a/arch/s390/include/asm/stacktrace.h
>>> +++ b/arch/s390/include/asm/stacktrace.h
>>> @@ -62,7 +62,7 @@ struct stack_frame {
>>> struct {
>>> unsigned long sie_control_block;
>>> unsigned long sie_savearea;
>>> - unsigned long sie_reason;
>>> + unsigned long sie_return;
>>> unsigned long sie_flags;
>>> unsigned long sie_control_block_phys;
>>> unsigned long sie_guest_asce;
>>> diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
>>> index e1a5b5b54e4f..fbd26f3e9f96 100644
>>> --- a/arch/s390/kernel/asm-offsets.c
>>> +++ b/arch/s390/kernel/asm-offsets.c
>>> @@ -63,7 +63,7 @@ int main(void)
>>> OFFSET(__SF_EMPTY, stack_frame, empty[0]);
>>> OFFSET(__SF_SIE_CONTROL, stack_frame, sie_control_block);
>>> OFFSET(__SF_SIE_SAVEAREA, stack_frame, sie_savearea);
>>> - OFFSET(__SF_SIE_REASON, stack_frame, sie_reason);
>>> + OFFSET(__SF_SIE_RETURN, stack_frame, sie_return);
>>> OFFSET(__SF_SIE_FLAGS, stack_frame, sie_flags);
>>> OFFSET(__SF_SIE_CONTROL_PHYS, stack_frame, sie_control_block_phys);
>>> OFFSET(__SF_SIE_GUEST_ASCE, stack_frame, sie_guest_asce);
>>> diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
>>> index 4873fe9d891b..5817cb47b2d0 100644
>>> --- a/arch/s390/kernel/entry.S
>>> +++ b/arch/s390/kernel/entry.S
>>> @@ -200,7 +200,7 @@ SYM_FUNC_START(__sie64a)
>>> stg %r3,__SF_SIE_CONTROL(%r15) # ...and virtual addresses
>>> stg %r4,__SF_SIE_SAVEAREA(%r15) # save guest register save area
>>> stg %r5,__SF_SIE_GUEST_ASCE(%r15) # save guest asce
>>> - xc __SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0
>>> + xc __SF_SIE_RETURN(8,%r15),__SF_SIE_RETURN(%r15) # return code = 0
>>> mvc __SF_SIE_FLAGS(8,%r15),__TI_flags(%r14) # copy thread flags
>>> lmg %r0,%r13,0(%r4) # load guest gprs 0-13
>>> mvi __TI_sie(%r14),1
>>> @@ -237,7 +237,7 @@ SYM_INNER_LABEL(sie_exit, SYM_L_GLOBAL)
>>> xgr %r4,%r4
>>> xgr %r5,%r5
>>> lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers
>>> - lg %r2,__SF_SIE_REASON(%r15) # return exit reason code
>>> + lg %r2,__SF_SIE_RETURN(%r15) # return sie return code
>>> BR_EX %r14
>>> SYM_FUNC_END(__sie64a)
>>> EXPORT_SYMBOL(__sie64a)
>>> diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
>>> index a55abbf65333..fc1f775e4517 100644
>>> --- a/arch/s390/kernel/nmi.c
>>> +++ b/arch/s390/kernel/nmi.c
>>> @@ -487,8 +487,8 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
>>> mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);
>>> if (test_cpu_flag(CIF_MCCK_GUEST) &&
>>> (mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {
>>> - /* Set exit reason code for host's later handling */
>>> - *((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;
>>> + /* Set sie return code for host's later handling */
>>> + *((long *)(regs->gprs[15] + __SF_SIE_RETURN)) = SIE64_RETURN_MCCK;
>>
>> We don't need to cast this to long anymore, do we?
>> Since sie_return is ulong, and we if we stay with positive numbers ulong would make the most sense.
>>
>> Although I'd prefer a cast to stack_frame but I'm unsure if that would make it more readable if we stay with a one line change.
> something like
> - *((long *)(regs->gprs[15] + __SF_SIE_RETURN)) = SIE64_RETURN_MCCK;
> + ((struct stack_frame *) regs->gprs[15])->sie_return = SIE64_RETURN_MCCK;>
> What do you think?
Yep
>
> This reminds me that I should probably also make the local variable in vsie.c unsigned long instead of int.
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-03-16 15:11 UTC | newest]
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2026-03-16 13:09 [PATCH v3] KVM: s390: vsie: Avoid injecting machine check on signal Christian Borntraeger
2026-03-16 13:13 ` Heiko Carstens
2026-03-16 13:42 ` Claudio Imbrenda
2026-03-16 13:57 ` Janosch Frank
2026-03-16 14:47 ` Christian Borntraeger
2026-03-16 15:11 ` Janosch Frank
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