2022-05-09 02:12:26

by Pierre Morel

[permalink] [raw]
Subject: [PATCH v9 1/3] s390x: KVM: ipte lock for SCA access should be contained in KVM

The former check to chose between SIIF or not SIIF can be done
using the sclp.has_siif instead of accessing per vCPU structures

When accessing the SCA, ipte lock and ipte_unlock do not need
to access any vcpu structures but only the KVM structure.

Let's simplify the ipte handling.

Signed-off-by: Pierre Morel <[email protected]>
---
arch/s390/kvm/gaccess.c | 96 ++++++++++++++++++++---------------------
arch/s390/kvm/gaccess.h | 6 +--
arch/s390/kvm/priv.c | 6 +--
3 files changed, 54 insertions(+), 54 deletions(-)

diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index d53a183c2005..0e1f6dd31882 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -262,77 +262,77 @@ struct aste {
/* .. more fields there */
};

-int ipte_lock_held(struct kvm_vcpu *vcpu)
+int ipte_lock_held(struct kvm *kvm)
{
- if (vcpu->arch.sie_block->eca & ECA_SII) {
+ if (sclp.has_siif) {
int rc;

- read_lock(&vcpu->kvm->arch.sca_lock);
- rc = kvm_s390_get_ipte_control(vcpu->kvm)->kh != 0;
- read_unlock(&vcpu->kvm->arch.sca_lock);
+ read_lock(&kvm->arch.sca_lock);
+ rc = kvm_s390_get_ipte_control(kvm)->kh != 0;
+ read_unlock(&kvm->arch.sca_lock);
return rc;
}
- return vcpu->kvm->arch.ipte_lock_count != 0;
+ return kvm->arch.ipte_lock_count != 0;
}

-static void ipte_lock_simple(struct kvm_vcpu *vcpu)
+static void ipte_lock_simple(struct kvm *kvm)
{
union ipte_control old, new, *ic;

- mutex_lock(&vcpu->kvm->arch.ipte_mutex);
- vcpu->kvm->arch.ipte_lock_count++;
- if (vcpu->kvm->arch.ipte_lock_count > 1)
+ mutex_lock(&kvm->arch.ipte_mutex);
+ kvm->arch.ipte_lock_count++;
+ if (kvm->arch.ipte_lock_count > 1)
goto out;
retry:
- read_lock(&vcpu->kvm->arch.sca_lock);
- ic = kvm_s390_get_ipte_control(vcpu->kvm);
+ read_lock(&kvm->arch.sca_lock);
+ ic = kvm_s390_get_ipte_control(kvm);
do {
old = READ_ONCE(*ic);
if (old.k) {
- read_unlock(&vcpu->kvm->arch.sca_lock);
+ read_unlock(&kvm->arch.sca_lock);
cond_resched();
goto retry;
}
new = old;
new.k = 1;
} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
- read_unlock(&vcpu->kvm->arch.sca_lock);
+ read_unlock(&kvm->arch.sca_lock);
out:
- mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
+ mutex_unlock(&kvm->arch.ipte_mutex);
}

-static void ipte_unlock_simple(struct kvm_vcpu *vcpu)
+static void ipte_unlock_simple(struct kvm *kvm)
{
union ipte_control old, new, *ic;

- mutex_lock(&vcpu->kvm->arch.ipte_mutex);
- vcpu->kvm->arch.ipte_lock_count--;
- if (vcpu->kvm->arch.ipte_lock_count)
+ mutex_lock(&kvm->arch.ipte_mutex);
+ kvm->arch.ipte_lock_count--;
+ if (kvm->arch.ipte_lock_count)
goto out;
- read_lock(&vcpu->kvm->arch.sca_lock);
- ic = kvm_s390_get_ipte_control(vcpu->kvm);
+ read_lock(&kvm->arch.sca_lock);
+ ic = kvm_s390_get_ipte_control(kvm);
do {
old = READ_ONCE(*ic);
new = old;
new.k = 0;
} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
- read_unlock(&vcpu->kvm->arch.sca_lock);
- wake_up(&vcpu->kvm->arch.ipte_wq);
+ read_unlock(&kvm->arch.sca_lock);
+ wake_up(&kvm->arch.ipte_wq);
out:
- mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
+ mutex_unlock(&kvm->arch.ipte_mutex);
}

-static void ipte_lock_siif(struct kvm_vcpu *vcpu)
+static void ipte_lock_siif(struct kvm *kvm)
{
union ipte_control old, new, *ic;

retry:
- read_lock(&vcpu->kvm->arch.sca_lock);
- ic = kvm_s390_get_ipte_control(vcpu->kvm);
+ read_lock(&kvm->arch.sca_lock);
+ ic = kvm_s390_get_ipte_control(kvm);
do {
old = READ_ONCE(*ic);
if (old.kg) {
- read_unlock(&vcpu->kvm->arch.sca_lock);
+ read_unlock(&kvm->arch.sca_lock);
cond_resched();
goto retry;
}
@@ -340,15 +340,15 @@ static void ipte_lock_siif(struct kvm_vcpu *vcpu)
new.k = 1;
new.kh++;
} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
- read_unlock(&vcpu->kvm->arch.sca_lock);
+ read_unlock(&kvm->arch.sca_lock);
}

-static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
+static void ipte_unlock_siif(struct kvm *kvm)
{
union ipte_control old, new, *ic;

- read_lock(&vcpu->kvm->arch.sca_lock);
- ic = kvm_s390_get_ipte_control(vcpu->kvm);
+ read_lock(&kvm->arch.sca_lock);
+ ic = kvm_s390_get_ipte_control(kvm);
do {
old = READ_ONCE(*ic);
new = old;
@@ -356,25 +356,25 @@ static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
if (!new.kh)
new.k = 0;
} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
- read_unlock(&vcpu->kvm->arch.sca_lock);
+ read_unlock(&kvm->arch.sca_lock);
if (!new.kh)
- wake_up(&vcpu->kvm->arch.ipte_wq);
+ wake_up(&kvm->arch.ipte_wq);
}

-void ipte_lock(struct kvm_vcpu *vcpu)
+void ipte_lock(struct kvm *kvm)
{
- if (vcpu->arch.sie_block->eca & ECA_SII)
- ipte_lock_siif(vcpu);
+ if (sclp.has_siif)
+ ipte_lock_siif(kvm);
else
- ipte_lock_simple(vcpu);
+ ipte_lock_simple(kvm);
}

-void ipte_unlock(struct kvm_vcpu *vcpu)
+void ipte_unlock(struct kvm *kvm)
{
- if (vcpu->arch.sie_block->eca & ECA_SII)
- ipte_unlock_siif(vcpu);
+ if (sclp.has_siif)
+ ipte_unlock_siif(kvm);
else
- ipte_unlock_simple(vcpu);
+ ipte_unlock_simple(kvm);
}

static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar,
@@ -1075,7 +1075,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
try_storage_prot_override = storage_prot_override_applicable(vcpu);
need_ipte_lock = psw_bits(*psw).dat && !asce.r;
if (need_ipte_lock)
- ipte_lock(vcpu);
+ ipte_lock(vcpu->kvm);
/*
* Since we do the access further down ultimately via a move instruction
* that does key checking and returns an error in case of a protection
@@ -1113,7 +1113,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
rc = trans_exc(vcpu, rc, ga, ar, mode, prot);
out_unlock:
if (need_ipte_lock)
- ipte_unlock(vcpu);
+ ipte_unlock(vcpu->kvm);
if (nr_pages > ARRAY_SIZE(gpa_array))
vfree(gpas);
return rc;
@@ -1185,10 +1185,10 @@ int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
if (rc)
return rc;
- ipte_lock(vcpu);
+ ipte_lock(vcpu->kvm);
rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode,
access_key);
- ipte_unlock(vcpu);
+ ipte_unlock(vcpu->kvm);

return rc;
}
@@ -1451,7 +1451,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
* tables/pointers we read stay valid - unshadowing is however
* always possible - only guest_table_lock protects us.
*/
- ipte_lock(vcpu);
+ ipte_lock(vcpu->kvm);

rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
if (rc)
@@ -1485,7 +1485,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
pte.p |= dat_protection;
if (!rc)
rc = gmap_shadow_page(sg, saddr, __pte(pte.val));
- ipte_unlock(vcpu);
+ ipte_unlock(vcpu->kvm);
mmap_read_unlock(sg->mm);
return rc;
}
diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index 1124ff282012..9408d6cc8e2c 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -440,9 +440,9 @@ int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
return access_guest_real(vcpu, gra, data, len, 0);
}

-void ipte_lock(struct kvm_vcpu *vcpu);
-void ipte_unlock(struct kvm_vcpu *vcpu);
-int ipte_lock_held(struct kvm_vcpu *vcpu);
+void ipte_lock(struct kvm *kvm);
+void ipte_unlock(struct kvm *kvm);
+int ipte_lock_held(struct kvm *kvm);
int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);

/* MVPG PEI indication bits */
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 5beb7a4a11b3..0e8603acc105 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -443,7 +443,7 @@ static int handle_ipte_interlock(struct kvm_vcpu *vcpu)
vcpu->stat.instruction_ipte_interlock++;
if (psw_bits(vcpu->arch.sie_block->gpsw).pstate)
return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
- wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu));
+ wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu->kvm));
kvm_s390_retry_instr(vcpu);
VCPU_EVENT(vcpu, 4, "%s", "retrying ipte interlock operation");
return 0;
@@ -1472,7 +1472,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
access_key = (operand2 & 0xf0) >> 4;

if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
- ipte_lock(vcpu);
+ ipte_lock(vcpu->kvm);

ret = guest_translate_address_with_key(vcpu, address, ar, &gpa,
GACC_STORE, access_key);
@@ -1509,7 +1509,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
}

if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
- ipte_unlock(vcpu);
+ ipte_unlock(vcpu->kvm);
return ret;
}

--
2.27.0



2022-05-12 22:38:36

by Janosch Frank

[permalink] [raw]
Subject: Re: [PATCH v9 1/3] s390x: KVM: ipte lock for SCA access should be contained in KVM

On 5/6/22 11:24, Pierre Morel wrote:
> The former check to chose between SIIF or not SIIF can be done
> using the sclp.has_siif instead of accessing per vCPU structures

Maybe replace this paragraph with:
We can check if SIIF is enabled by testing the sclp_info struct instead
of testing the sie control block eca variable. sclp.has_ssif is the only
requirement to set ECA_SII anyway so we can go straight to the source
for that.

Reviewed-by: Janosch Frank <[email protected]>

>
> When accessing the SCA, ipte lock and ipte_unlock do not need
> to access any vcpu structures but only the KVM structure.
>
> Let's simplify the ipte handling.
>
> Signed-off-by: Pierre Morel <[email protected]>
> ---
> arch/s390/kvm/gaccess.c | 96 ++++++++++++++++++++---------------------
> arch/s390/kvm/gaccess.h | 6 +--
> arch/s390/kvm/priv.c | 6 +--
> 3 files changed, 54 insertions(+), 54 deletions(-)
>
> diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
> index d53a183c2005..0e1f6dd31882 100644
> --- a/arch/s390/kvm/gaccess.c
> +++ b/arch/s390/kvm/gaccess.c
> @@ -262,77 +262,77 @@ struct aste {
> /* .. more fields there */
> };
>
> -int ipte_lock_held(struct kvm_vcpu *vcpu)
> +int ipte_lock_held(struct kvm *kvm)
> {
> - if (vcpu->arch.sie_block->eca & ECA_SII) {
> + if (sclp.has_siif) {
> int rc;
>
> - read_lock(&vcpu->kvm->arch.sca_lock);
> - rc = kvm_s390_get_ipte_control(vcpu->kvm)->kh != 0;
> - read_unlock(&vcpu->kvm->arch.sca_lock);
> + read_lock(&kvm->arch.sca_lock);
> + rc = kvm_s390_get_ipte_control(kvm)->kh != 0;
> + read_unlock(&kvm->arch.sca_lock);
> return rc;
> }
> - return vcpu->kvm->arch.ipte_lock_count != 0;
> + return kvm->arch.ipte_lock_count != 0;
> }
>
> -static void ipte_lock_simple(struct kvm_vcpu *vcpu)
> +static void ipte_lock_simple(struct kvm *kvm)
> {
> union ipte_control old, new, *ic;
>
> - mutex_lock(&vcpu->kvm->arch.ipte_mutex);
> - vcpu->kvm->arch.ipte_lock_count++;
> - if (vcpu->kvm->arch.ipte_lock_count > 1)
> + mutex_lock(&kvm->arch.ipte_mutex);
> + kvm->arch.ipte_lock_count++;
> + if (kvm->arch.ipte_lock_count > 1)
> goto out;
> retry:
> - read_lock(&vcpu->kvm->arch.sca_lock);
> - ic = kvm_s390_get_ipte_control(vcpu->kvm);
> + read_lock(&kvm->arch.sca_lock);
> + ic = kvm_s390_get_ipte_control(kvm);
> do {
> old = READ_ONCE(*ic);
> if (old.k) {
> - read_unlock(&vcpu->kvm->arch.sca_lock);
> + read_unlock(&kvm->arch.sca_lock);
> cond_resched();
> goto retry;
> }
> new = old;
> new.k = 1;
> } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
> - read_unlock(&vcpu->kvm->arch.sca_lock);
> + read_unlock(&kvm->arch.sca_lock);
> out:
> - mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
> + mutex_unlock(&kvm->arch.ipte_mutex);
> }
>
> -static void ipte_unlock_simple(struct kvm_vcpu *vcpu)
> +static void ipte_unlock_simple(struct kvm *kvm)
> {
> union ipte_control old, new, *ic;
>
> - mutex_lock(&vcpu->kvm->arch.ipte_mutex);
> - vcpu->kvm->arch.ipte_lock_count--;
> - if (vcpu->kvm->arch.ipte_lock_count)
> + mutex_lock(&kvm->arch.ipte_mutex);
> + kvm->arch.ipte_lock_count--;
> + if (kvm->arch.ipte_lock_count)
> goto out;
> - read_lock(&vcpu->kvm->arch.sca_lock);
> - ic = kvm_s390_get_ipte_control(vcpu->kvm);
> + read_lock(&kvm->arch.sca_lock);
> + ic = kvm_s390_get_ipte_control(kvm);
> do {
> old = READ_ONCE(*ic);
> new = old;
> new.k = 0;
> } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
> - read_unlock(&vcpu->kvm->arch.sca_lock);
> - wake_up(&vcpu->kvm->arch.ipte_wq);
> + read_unlock(&kvm->arch.sca_lock);
> + wake_up(&kvm->arch.ipte_wq);
> out:
> - mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
> + mutex_unlock(&kvm->arch.ipte_mutex);
> }
>
> -static void ipte_lock_siif(struct kvm_vcpu *vcpu)
> +static void ipte_lock_siif(struct kvm *kvm)
> {
> union ipte_control old, new, *ic;
>
> retry:
> - read_lock(&vcpu->kvm->arch.sca_lock);
> - ic = kvm_s390_get_ipte_control(vcpu->kvm);
> + read_lock(&kvm->arch.sca_lock);
> + ic = kvm_s390_get_ipte_control(kvm);
> do {
> old = READ_ONCE(*ic);
> if (old.kg) {
> - read_unlock(&vcpu->kvm->arch.sca_lock);
> + read_unlock(&kvm->arch.sca_lock);
> cond_resched();
> goto retry;
> }
> @@ -340,15 +340,15 @@ static void ipte_lock_siif(struct kvm_vcpu *vcpu)
> new.k = 1;
> new.kh++;
> } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
> - read_unlock(&vcpu->kvm->arch.sca_lock);
> + read_unlock(&kvm->arch.sca_lock);
> }
>
> -static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
> +static void ipte_unlock_siif(struct kvm *kvm)
> {
> union ipte_control old, new, *ic;
>
> - read_lock(&vcpu->kvm->arch.sca_lock);
> - ic = kvm_s390_get_ipte_control(vcpu->kvm);
> + read_lock(&kvm->arch.sca_lock);
> + ic = kvm_s390_get_ipte_control(kvm);
> do {
> old = READ_ONCE(*ic);
> new = old;
> @@ -356,25 +356,25 @@ static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
> if (!new.kh)
> new.k = 0;
> } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
> - read_unlock(&vcpu->kvm->arch.sca_lock);
> + read_unlock(&kvm->arch.sca_lock);
> if (!new.kh)
> - wake_up(&vcpu->kvm->arch.ipte_wq);
> + wake_up(&kvm->arch.ipte_wq);
> }
>
> -void ipte_lock(struct kvm_vcpu *vcpu)
> +void ipte_lock(struct kvm *kvm)
> {
> - if (vcpu->arch.sie_block->eca & ECA_SII)
> - ipte_lock_siif(vcpu);
> + if (sclp.has_siif)
> + ipte_lock_siif(kvm);
> else
> - ipte_lock_simple(vcpu);
> + ipte_lock_simple(kvm);
> }
>
> -void ipte_unlock(struct kvm_vcpu *vcpu)
> +void ipte_unlock(struct kvm *kvm)
> {
> - if (vcpu->arch.sie_block->eca & ECA_SII)
> - ipte_unlock_siif(vcpu);
> + if (sclp.has_siif)
> + ipte_unlock_siif(kvm);
> else
> - ipte_unlock_simple(vcpu);
> + ipte_unlock_simple(kvm);
> }
>
> static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar,
> @@ -1075,7 +1075,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
> try_storage_prot_override = storage_prot_override_applicable(vcpu);
> need_ipte_lock = psw_bits(*psw).dat && !asce.r;
> if (need_ipte_lock)
> - ipte_lock(vcpu);
> + ipte_lock(vcpu->kvm);
> /*
> * Since we do the access further down ultimately via a move instruction
> * that does key checking and returns an error in case of a protection
> @@ -1113,7 +1113,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
> rc = trans_exc(vcpu, rc, ga, ar, mode, prot);
> out_unlock:
> if (need_ipte_lock)
> - ipte_unlock(vcpu);
> + ipte_unlock(vcpu->kvm);
> if (nr_pages > ARRAY_SIZE(gpa_array))
> vfree(gpas);
> return rc;
> @@ -1185,10 +1185,10 @@ int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
> rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
> if (rc)
> return rc;
> - ipte_lock(vcpu);
> + ipte_lock(vcpu->kvm);
> rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode,
> access_key);
> - ipte_unlock(vcpu);
> + ipte_unlock(vcpu->kvm);
>
> return rc;
> }
> @@ -1451,7 +1451,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
> * tables/pointers we read stay valid - unshadowing is however
> * always possible - only guest_table_lock protects us.
> */
> - ipte_lock(vcpu);
> + ipte_lock(vcpu->kvm);
>
> rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
> if (rc)
> @@ -1485,7 +1485,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
> pte.p |= dat_protection;
> if (!rc)
> rc = gmap_shadow_page(sg, saddr, __pte(pte.val));
> - ipte_unlock(vcpu);
> + ipte_unlock(vcpu->kvm);
> mmap_read_unlock(sg->mm);
> return rc;
> }
> diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
> index 1124ff282012..9408d6cc8e2c 100644
> --- a/arch/s390/kvm/gaccess.h
> +++ b/arch/s390/kvm/gaccess.h
> @@ -440,9 +440,9 @@ int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
> return access_guest_real(vcpu, gra, data, len, 0);
> }
>
> -void ipte_lock(struct kvm_vcpu *vcpu);
> -void ipte_unlock(struct kvm_vcpu *vcpu);
> -int ipte_lock_held(struct kvm_vcpu *vcpu);
> +void ipte_lock(struct kvm *kvm);
> +void ipte_unlock(struct kvm *kvm);
> +int ipte_lock_held(struct kvm *kvm);
> int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);
>
> /* MVPG PEI indication bits */
> diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
> index 5beb7a4a11b3..0e8603acc105 100644
> --- a/arch/s390/kvm/priv.c
> +++ b/arch/s390/kvm/priv.c
> @@ -443,7 +443,7 @@ static int handle_ipte_interlock(struct kvm_vcpu *vcpu)
> vcpu->stat.instruction_ipte_interlock++;
> if (psw_bits(vcpu->arch.sie_block->gpsw).pstate)
> return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
> - wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu));
> + wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu->kvm));
> kvm_s390_retry_instr(vcpu);
> VCPU_EVENT(vcpu, 4, "%s", "retrying ipte interlock operation");
> return 0;
> @@ -1472,7 +1472,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
> access_key = (operand2 & 0xf0) >> 4;
>
> if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
> - ipte_lock(vcpu);
> + ipte_lock(vcpu->kvm);
>
> ret = guest_translate_address_with_key(vcpu, address, ar, &gpa,
> GACC_STORE, access_key);
> @@ -1509,7 +1509,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
> }
>
> if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
> - ipte_unlock(vcpu);
> + ipte_unlock(vcpu->kvm);
> return ret;
> }
>


2022-05-13 06:14:52

by David Hildenbrand

[permalink] [raw]
Subject: Re: [PATCH v9 1/3] s390x: KVM: ipte lock for SCA access should be contained in KVM

On 06.05.22 11:24, Pierre Morel wrote:
> The former check to chose between SIIF or not SIIF can be done
> using the sclp.has_siif instead of accessing per vCPU structures
>
> When accessing the SCA, ipte lock and ipte_unlock do not need
> to access any vcpu structures but only the KVM structure.
>
> Let's simplify the ipte handling.
>
> Signed-off-by: Pierre Morel <[email protected]>

Much better

Reviewed-by: David Hildenbrand <[email protected]>


--
Thanks,

David / dhildenb


2022-05-17 01:49:44

by Pierre Morel

[permalink] [raw]
Subject: Re: [PATCH v9 1/3] s390x: KVM: ipte lock for SCA access should be contained in KVM



On 5/12/22 11:08, David Hildenbrand wrote:
> On 06.05.22 11:24, Pierre Morel wrote:
>> The former check to chose between SIIF or not SIIF can be done
>> using the sclp.has_siif instead of accessing per vCPU structures
>>
>> When accessing the SCA, ipte lock and ipte_unlock do not need
>> to access any vcpu structures but only the KVM structure.
>>
>> Let's simplify the ipte handling.
>>
>> Signed-off-by: Pierre Morel <[email protected]>
>
> Much better
>
> Reviewed-by: David Hildenbrand <[email protected]>
>
>

Thanks,
Regards,

Pierre

--
Pierre Morel
IBM Lab Boeblingen

2022-05-17 03:23:29

by Pierre Morel

[permalink] [raw]
Subject: Re: [PATCH v9 1/3] s390x: KVM: ipte lock for SCA access should be contained in KVM



On 5/12/22 13:32, Janosch Frank wrote:
> On 5/6/22 11:24, Pierre Morel wrote:
>> The former check to chose between SIIF or not SIIF can be done
>> using the sclp.has_siif instead of accessing per vCPU structures
>
> Maybe replace this paragraph with:
> We can check if SIIF is enabled by testing the sclp_info struct instead
> of testing the sie control block eca variable. sclp.has_ssif is the only
> requirement to set ECA_SII anyway so we can go straight to the source
> for that.
>
> Reviewed-by: Janosch Frank <[email protected]>

OK, thanks,

Regards,
Pierre

>
>>
>> When accessing the SCA, ipte lock and ipte_unlock do not need
>> to access any vcpu structures but only the KVM structure.
>>
>> Let's simplify the ipte handling.
>>
>> Signed-off-by: Pierre Morel <[email protected]>
>> ---
>>   arch/s390/kvm/gaccess.c | 96 ++++++++++++++++++++---------------------
>>   arch/s390/kvm/gaccess.h |  6 +--
>>   arch/s390/kvm/priv.c    |  6 +--
>>   3 files changed, 54 insertions(+), 54 deletions(-)
>>
>> diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
>> index d53a183c2005..0e1f6dd31882 100644
>> --- a/arch/s390/kvm/gaccess.c
>> +++ b/arch/s390/kvm/gaccess.c
>> @@ -262,77 +262,77 @@ struct aste {
>>       /* .. more fields there */
>>   };
>> -int ipte_lock_held(struct kvm_vcpu *vcpu)
>> +int ipte_lock_held(struct kvm *kvm)
>>   {
>> -    if (vcpu->arch.sie_block->eca & ECA_SII) {
>> +    if (sclp.has_siif) {
>>           int rc;
>> -        read_lock(&vcpu->kvm->arch.sca_lock);
>> -        rc = kvm_s390_get_ipte_control(vcpu->kvm)->kh != 0;
>> -        read_unlock(&vcpu->kvm->arch.sca_lock);
>> +        read_lock(&kvm->arch.sca_lock);
>> +        rc = kvm_s390_get_ipte_control(kvm)->kh != 0;
>> +        read_unlock(&kvm->arch.sca_lock);
>>           return rc;
>>       }
>> -    return vcpu->kvm->arch.ipte_lock_count != 0;
>> +    return kvm->arch.ipte_lock_count != 0;
>>   }
>> -static void ipte_lock_simple(struct kvm_vcpu *vcpu)
>> +static void ipte_lock_simple(struct kvm *kvm)
>>   {
>>       union ipte_control old, new, *ic;
>> -    mutex_lock(&vcpu->kvm->arch.ipte_mutex);
>> -    vcpu->kvm->arch.ipte_lock_count++;
>> -    if (vcpu->kvm->arch.ipte_lock_count > 1)
>> +    mutex_lock(&kvm->arch.ipte_mutex);
>> +    kvm->arch.ipte_lock_count++;
>> +    if (kvm->arch.ipte_lock_count > 1)
>>           goto out;
>>   retry:
>> -    read_lock(&vcpu->kvm->arch.sca_lock);
>> -    ic = kvm_s390_get_ipte_control(vcpu->kvm);
>> +    read_lock(&kvm->arch.sca_lock);
>> +    ic = kvm_s390_get_ipte_control(kvm);
>>       do {
>>           old = READ_ONCE(*ic);
>>           if (old.k) {
>> -            read_unlock(&vcpu->kvm->arch.sca_lock);
>> +            read_unlock(&kvm->arch.sca_lock);
>>               cond_resched();
>>               goto retry;
>>           }
>>           new = old;
>>           new.k = 1;
>>       } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
>> -    read_unlock(&vcpu->kvm->arch.sca_lock);
>> +    read_unlock(&kvm->arch.sca_lock);
>>   out:
>> -    mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
>> +    mutex_unlock(&kvm->arch.ipte_mutex);
>>   }
>> -static void ipte_unlock_simple(struct kvm_vcpu *vcpu)
>> +static void ipte_unlock_simple(struct kvm *kvm)
>>   {
>>       union ipte_control old, new, *ic;
>> -    mutex_lock(&vcpu->kvm->arch.ipte_mutex);
>> -    vcpu->kvm->arch.ipte_lock_count--;
>> -    if (vcpu->kvm->arch.ipte_lock_count)
>> +    mutex_lock(&kvm->arch.ipte_mutex);
>> +    kvm->arch.ipte_lock_count--;
>> +    if (kvm->arch.ipte_lock_count)
>>           goto out;
>> -    read_lock(&vcpu->kvm->arch.sca_lock);
>> -    ic = kvm_s390_get_ipte_control(vcpu->kvm);
>> +    read_lock(&kvm->arch.sca_lock);
>> +    ic = kvm_s390_get_ipte_control(kvm);
>>       do {
>>           old = READ_ONCE(*ic);
>>           new = old;
>>           new.k = 0;
>>       } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
>> -    read_unlock(&vcpu->kvm->arch.sca_lock);
>> -    wake_up(&vcpu->kvm->arch.ipte_wq);
>> +    read_unlock(&kvm->arch.sca_lock);
>> +    wake_up(&kvm->arch.ipte_wq);
>>   out:
>> -    mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
>> +    mutex_unlock(&kvm->arch.ipte_mutex);
>>   }
>> -static void ipte_lock_siif(struct kvm_vcpu *vcpu)
>> +static void ipte_lock_siif(struct kvm *kvm)
>>   {
>>       union ipte_control old, new, *ic;
>>   retry:
>> -    read_lock(&vcpu->kvm->arch.sca_lock);
>> -    ic = kvm_s390_get_ipte_control(vcpu->kvm);
>> +    read_lock(&kvm->arch.sca_lock);
>> +    ic = kvm_s390_get_ipte_control(kvm);
>>       do {
>>           old = READ_ONCE(*ic);
>>           if (old.kg) {
>> -            read_unlock(&vcpu->kvm->arch.sca_lock);
>> +            read_unlock(&kvm->arch.sca_lock);
>>               cond_resched();
>>               goto retry;
>>           }
>> @@ -340,15 +340,15 @@ static void ipte_lock_siif(struct kvm_vcpu *vcpu)
>>           new.k = 1;
>>           new.kh++;
>>       } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
>> -    read_unlock(&vcpu->kvm->arch.sca_lock);
>> +    read_unlock(&kvm->arch.sca_lock);
>>   }
>> -static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
>> +static void ipte_unlock_siif(struct kvm *kvm)
>>   {
>>       union ipte_control old, new, *ic;
>> -    read_lock(&vcpu->kvm->arch.sca_lock);
>> -    ic = kvm_s390_get_ipte_control(vcpu->kvm);
>> +    read_lock(&kvm->arch.sca_lock);
>> +    ic = kvm_s390_get_ipte_control(kvm);
>>       do {
>>           old = READ_ONCE(*ic);
>>           new = old;
>> @@ -356,25 +356,25 @@ static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
>>           if (!new.kh)
>>               new.k = 0;
>>       } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
>> -    read_unlock(&vcpu->kvm->arch.sca_lock);
>> +    read_unlock(&kvm->arch.sca_lock);
>>       if (!new.kh)
>> -        wake_up(&vcpu->kvm->arch.ipte_wq);
>> +        wake_up(&kvm->arch.ipte_wq);
>>   }
>> -void ipte_lock(struct kvm_vcpu *vcpu)
>> +void ipte_lock(struct kvm *kvm)
>>   {
>> -    if (vcpu->arch.sie_block->eca & ECA_SII)
>> -        ipte_lock_siif(vcpu);
>> +    if (sclp.has_siif)
>> +        ipte_lock_siif(kvm);
>>       else
>> -        ipte_lock_simple(vcpu);
>> +        ipte_lock_simple(kvm);
>>   }
>> -void ipte_unlock(struct kvm_vcpu *vcpu)
>> +void ipte_unlock(struct kvm *kvm)
>>   {
>> -    if (vcpu->arch.sie_block->eca & ECA_SII)
>> -        ipte_unlock_siif(vcpu);
>> +    if (sclp.has_siif)
>> +        ipte_unlock_siif(kvm);
>>       else
>> -        ipte_unlock_simple(vcpu);
>> +        ipte_unlock_simple(kvm);
>>   }
>>   static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce,
>> u8 ar,
>> @@ -1075,7 +1075,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu,
>> unsigned long ga, u8 ar,
>>       try_storage_prot_override = storage_prot_override_applicable(vcpu);
>>       need_ipte_lock = psw_bits(*psw).dat && !asce.r;
>>       if (need_ipte_lock)
>> -        ipte_lock(vcpu);
>> +        ipte_lock(vcpu->kvm);
>>       /*
>>        * Since we do the access further down ultimately via a move
>> instruction
>>        * that does key checking and returns an error in case of a
>> protection
>> @@ -1113,7 +1113,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu,
>> unsigned long ga, u8 ar,
>>           rc = trans_exc(vcpu, rc, ga, ar, mode, prot);
>>   out_unlock:
>>       if (need_ipte_lock)
>> -        ipte_unlock(vcpu);
>> +        ipte_unlock(vcpu->kvm);
>>       if (nr_pages > ARRAY_SIZE(gpa_array))
>>           vfree(gpas);
>>       return rc;
>> @@ -1185,10 +1185,10 @@ int check_gva_range(struct kvm_vcpu *vcpu,
>> unsigned long gva, u8 ar,
>>       rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
>>       if (rc)
>>           return rc;
>> -    ipte_lock(vcpu);
>> +    ipte_lock(vcpu->kvm);
>>       rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode,
>>                    access_key);
>> -    ipte_unlock(vcpu);
>> +    ipte_unlock(vcpu->kvm);
>>       return rc;
>>   }
>> @@ -1451,7 +1451,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu,
>> struct gmap *sg,
>>        * tables/pointers we read stay valid - unshadowing is however
>>        * always possible - only guest_table_lock protects us.
>>        */
>> -    ipte_lock(vcpu);
>> +    ipte_lock(vcpu->kvm);
>>       rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection,
>> &fake);
>>       if (rc)
>> @@ -1485,7 +1485,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu,
>> struct gmap *sg,
>>       pte.p |= dat_protection;
>>       if (!rc)
>>           rc = gmap_shadow_page(sg, saddr, __pte(pte.val));
>> -    ipte_unlock(vcpu);
>> +    ipte_unlock(vcpu->kvm);
>>       mmap_read_unlock(sg->mm);
>>       return rc;
>>   }
>> diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
>> index 1124ff282012..9408d6cc8e2c 100644
>> --- a/arch/s390/kvm/gaccess.h
>> +++ b/arch/s390/kvm/gaccess.h
>> @@ -440,9 +440,9 @@ int read_guest_real(struct kvm_vcpu *vcpu,
>> unsigned long gra, void *data,
>>       return access_guest_real(vcpu, gra, data, len, 0);
>>   }
>> -void ipte_lock(struct kvm_vcpu *vcpu);
>> -void ipte_unlock(struct kvm_vcpu *vcpu);
>> -int ipte_lock_held(struct kvm_vcpu *vcpu);
>> +void ipte_lock(struct kvm *kvm);
>> +void ipte_unlock(struct kvm *kvm);
>> +int ipte_lock_held(struct kvm *kvm);
>>   int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu,
>> unsigned long gra);
>>   /* MVPG PEI indication bits */
>> diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
>> index 5beb7a4a11b3..0e8603acc105 100644
>> --- a/arch/s390/kvm/priv.c
>> +++ b/arch/s390/kvm/priv.c
>> @@ -443,7 +443,7 @@ static int handle_ipte_interlock(struct kvm_vcpu
>> *vcpu)
>>       vcpu->stat.instruction_ipte_interlock++;
>>       if (psw_bits(vcpu->arch.sie_block->gpsw).pstate)
>>           return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
>> -    wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu));
>> +    wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu->kvm));
>>       kvm_s390_retry_instr(vcpu);
>>       VCPU_EVENT(vcpu, 4, "%s", "retrying ipte interlock operation");
>>       return 0;
>> @@ -1472,7 +1472,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
>>       access_key = (operand2 & 0xf0) >> 4;
>>       if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
>> -        ipte_lock(vcpu);
>> +        ipte_lock(vcpu->kvm);
>>       ret = guest_translate_address_with_key(vcpu, address, ar, &gpa,
>>                              GACC_STORE, access_key);
>> @@ -1509,7 +1509,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
>>       }
>>       if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
>> -        ipte_unlock(vcpu);
>> +        ipte_unlock(vcpu->kvm);
>>       return ret;
>>   }
>

--
Pierre Morel
IBM Lab Boeblingen