From: "Alex Bennée" <alex.bennee@linaro.org>
To: qemu-devel@nongnu.org
Cc: Thomas Huth <thuth@redhat.com>,
Janosch Frank <frankja@linux.ibm.com>,
David Hildenbrand <david@redhat.com>,
Cornelia Huck <cohuck@redhat.com>,
Halil Pasic <pasic@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
qemu-s390x@nongnu.org, Richard Henderson <rth@twiddle.net>
Subject: Re: [Qemu-devel] [PATCH-for-4.2 v2 3/6] s390x/tcg: Flush the TLB of all CPUs on SSKE and RRBE
Date: Wed, 14 Aug 2019 11:06:55 +0100 [thread overview]
Message-ID: <87wofgm56o.fsf@linaro.org> (raw)
In-Reply-To: <20190814072355.15333-4-david@redhat.com>
David Hildenbrand <david@redhat.com> writes:
> Whenever we modify a storage key, we shuld flush the TLBs of all CPUs,
> so the MMU fault handling code can properly consider the changed storage
> key (to e.g., properly set the reference and change bit on the next
> accesses).
>
> These functions are barely used in modern Linux guests, so the performance
> implications are neglectable for now.
>
> This is a preparation for better reference and change bit handling for
> TCG, which will require more MMU changes.
>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> target/s390x/mem_helper.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c
> index 29d9eaa5b7..ed54265e03 100644
> --- a/target/s390x/mem_helper.c
> +++ b/target/s390x/mem_helper.c
> @@ -1815,6 +1815,8 @@ void HELPER(sske)(CPUS390XState *env, uint64_t r1, uint64_t r2)
>
> key = (uint8_t) r1;
> skeyclass->set_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
> + /* TODO: Flush only entries with this target address */
> + tlb_flush_all_cpus_synced(env_cpu(env));
Doesn't:
tlb_flush_page_all_cpus_synced(env_cpu(env), addr & TARGET_PAGE_MASK);
do what you want here?
> }
>
> /* reset reference bit extended */
> @@ -1843,6 +1845,8 @@ uint32_t HELPER(rrbe)(CPUS390XState *env, uint64_t r2)
> if (skeyclass->set_skeys(ss, r2 / TARGET_PAGE_SIZE, 1, &key)) {
> return 0;
> }
> + /* TODO: Flush only entries with this target address */
> + tlb_flush_all_cpus_synced(env_cpu(env));
>
> /*
> * cc
--
Alex Bennée
next prev parent reply other threads:[~2019-08-14 10:08 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-14 7:23 [Qemu-devel] [PATCH-for-4.2 v2 0/6] s390x/mmu: Storage key reference and change bit handling David Hildenbrand
2019-08-14 7:23 ` [Qemu-devel] [PATCH-for-4.2 v2 1/6] s390x/mmu: ASC selection in s390_cpu_get_phys_page_debug() David Hildenbrand
2019-08-14 7:23 ` [Qemu-devel] [PATCH-for-4.2 v2 2/6] s390x/tcg: Rework MMU selection for instruction fetches David Hildenbrand
2019-08-14 17:44 ` [Qemu-devel] [qemu-s390x] " Thomas Huth
2019-08-15 15:43 ` [Qemu-devel] " Cornelia Huck
2019-08-15 16:52 ` David Hildenbrand
2019-08-14 7:23 ` [Qemu-devel] [PATCH-for-4.2 v2 3/6] s390x/tcg: Flush the TLB of all CPUs on SSKE and RRBE David Hildenbrand
2019-08-14 10:06 ` Alex Bennée [this message]
2019-08-14 10:21 ` David Hildenbrand
2019-08-14 10:44 ` Alex Bennée
2019-08-14 10:51 ` David Hildenbrand
2019-08-14 7:23 ` [Qemu-devel] [PATCH-for-4.2 v2 4/6] s390x/mmu: Trace the right value if setting/getting the storage key fails David Hildenbrand
2019-08-14 17:50 ` [Qemu-devel] [qemu-s390x] " Thomas Huth
2019-08-15 15:39 ` Cornelia Huck
2019-08-14 7:23 ` [Qemu-devel] [PATCH-for-4.2 v2 5/6] s390x/mmu: Better storage key reference and change bit handling David Hildenbrand
2019-08-14 7:23 ` [Qemu-devel] [PATCH-for-4.2 v2 6/6] s390x/mmu: Factor out storage key handling David Hildenbrand
2019-08-14 18:01 ` [Qemu-devel] [qemu-s390x] " Thomas Huth
2019-08-14 18:18 ` David Hildenbrand
2019-08-19 16:36 ` [Qemu-devel] [PATCH-for-4.2 v2 0/6] s390x/mmu: Storage key reference and change bit handling Cornelia Huck
2019-08-19 16:37 ` Cornelia Huck
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