From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Leonardo Bras <leonardo@linux.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Arnd Bergmann <arnd@arndb.de>,
Andrew Morton <akpm@linux-foundation.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Nicholas Piggin <npiggin@gmail.com>,
Steven Price <steven.price@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
Balbir Singh <bsingharora@gmail.com>,
Reza Arbab <arbab@linux.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Allison Randal <allison@lohutok.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Mike Rapoport <rppt@linux.ibm.com>,
Michal Suchanek <msuchanek@suse.de>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH v6 07/11] powerpc/kvm/e500: Use functions to track lockless pgtbl walks
Date: Thu, 6 Feb 2020 07:18:02 +0100 [thread overview]
Message-ID: <fae235d5-78b6-87aa-ed3f-1a908d61abf4@c-s.fr> (raw)
In-Reply-To: <20200206030900.147032-8-leonardo@linux.ibm.com>
Le 06/02/2020 à 04:08, Leonardo Bras a écrit :
> Applies the new functions used for tracking lockless pgtable walks on
> kvmppc_e500_shadow_map().
>
> Fixes the place where local_irq_restore() is called: previously, if ptep
> was NULL, local_irq_restore() would never be called.
>
> local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_walk,
> so there is no need to repeat it here.
>
> Variable that saves the irq mask was renamed from flags to irq_mask so it
> doesn't lose meaning now it's not directly passed to local_irq_* functions.
>
> Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
> ---
> arch/powerpc/kvm/e500_mmu_host.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
> index 425d13806645..3dcf11f77256 100644
> --- a/arch/powerpc/kvm/e500_mmu_host.c
> +++ b/arch/powerpc/kvm/e500_mmu_host.c
> @@ -336,7 +336,7 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
> pte_t *ptep;
> unsigned int wimg = 0;
> pgd_t *pgdir;
> - unsigned long flags;
> + unsigned long irq_mask;
>
> /* used to check for invalidations in progress */
> mmu_seq = kvm->mmu_notifier_seq;
> @@ -473,7 +473,7 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
> * We are holding kvm->mmu_lock so a notifier invalidate
> * can't run hence pfn won't change.
> */
> - local_irq_save(flags);
> + irq_mask = begin_lockless_pgtbl_walk();
> ptep = find_linux_pte(pgdir, hva, NULL, NULL);
> if (ptep) {
> pte_t pte = READ_ONCE(*ptep);
> @@ -481,15 +481,16 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
> if (pte_present(pte)) {
> wimg = (pte_val(pte) >> PTE_WIMGE_SHIFT) &
> MAS2_WIMGE_MASK;
> - local_irq_restore(flags);
> } else {
> - local_irq_restore(flags);
> + end_lockless_pgtbl_walk(irq_mask);
> pr_err_ratelimited("%s: pte not present: gfn %lx,pfn %lx\n",
> __func__, (long)gfn, pfn);
> ret = -EINVAL;
> goto out;
> }
> }
> + end_lockless_pgtbl_walk(irq_mask);
> +
I don't really like unbalanced begin/end.
Something like the following would be cleaner:
begin_lockless_pgtbl_walk()
ptep = find()
if (ptep) {
pte = READ_ONCE()
if (pte_present(pte))
wing=
else
ret = -EINVAL;
}
end_lockless_pgtbl_walk()
if (ret) {
pr_err_rate...()
goto out;
}
> kvmppc_e500_ref_setup(ref, gtlbe, pfn, wimg);
>
> kvmppc_e500_setup_stlbe(&vcpu_e500->vcpu, gtlbe, tsize,
>
Christophe
next prev parent reply other threads:[~2020-02-06 6:18 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-06 3:08 [PATCH v6 00/11] Introduces new functions for tracking lockless pagetable walks Leonardo Bras
2020-02-06 3:08 ` [PATCH v6 01/11] asm-generic/pgtable: Adds generic functions to track lockless pgtable walks Leonardo Bras
2020-02-06 5:54 ` Christophe Leroy
2020-02-07 2:19 ` Leonardo Bras
2020-02-07 5:39 ` kbuild test robot
2020-02-06 3:08 ` [PATCH v6 02/11] mm/gup: Use functions to track lockless pgtbl walks on gup_pgd_range Leonardo Bras
2020-02-06 3:25 ` Leonardo Bras
[not found] ` <0c2f5a89-4890-fd84-6a6d-e470ba110399@nvidia.com>
2020-02-17 20:55 ` Leonardo Bras
2020-10-15 14:46 ` Michal Suchánek
2020-10-16 3:27 ` Aneesh Kumar K.V
2020-02-07 1:19 ` kbuild test robot
2020-02-07 8:01 ` kbuild test robot
2020-02-06 3:08 ` [PATCH v6 03/11] powerpc/mm: Adds arch-specificic functions to track lockless pgtable walks Leonardo Bras
2020-02-06 5:46 ` Christophe Leroy
2020-02-07 4:38 ` Leonardo Bras
2020-02-17 20:32 ` Leonardo Bras
2020-02-06 3:08 ` [PATCH v6 04/11] powerpc/mce_power: Use functions to track lockless pgtbl walks Leonardo Bras
2020-02-06 5:48 ` Christophe Leroy
2020-02-07 4:00 ` Leonardo Bras
2020-02-06 3:08 ` [PATCH v6 05/11] powerpc/perf: " Leonardo Bras
2020-02-06 3:08 ` [PATCH v6 06/11] powerpc/mm/book3s64/hash: " Leonardo Bras
2020-02-06 6:06 ` Christophe Leroy
2020-02-07 3:49 ` Leonardo Bras
2020-02-06 3:08 ` [PATCH v6 07/11] powerpc/kvm/e500: " Leonardo Bras
2020-02-06 6:18 ` Christophe Leroy [this message]
2020-02-07 3:10 ` Leonardo Bras
2020-02-06 3:08 ` [PATCH v6 08/11] powerpc/kvm/book3s_hv: " Leonardo Bras
2020-02-06 3:08 ` [PATCH v6 09/11] powerpc/kvm/book3s_64: " Leonardo Bras
2020-02-06 3:08 ` [PATCH v6 10/11] powerpc/mm: Adds counting method to track lockless pagetable walks Leonardo Bras
2020-02-06 6:23 ` Christophe Leroy
2020-02-07 1:56 ` Leonardo Bras
2020-02-06 3:09 ` [PATCH v6 11/11] powerpc/mm/book3s64/pgtable: Uses counting method to skip serializing Leonardo Bras
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=fae235d5-78b6-87aa-ed3f-1a908d61abf4@c-s.fr \
--to=christophe.leroy@c-s.fr \
--cc=akpm@linux-foundation.org \
--cc=allison@lohutok.net \
--cc=aneesh.kumar@linux.ibm.com \
--cc=arbab@linux.ibm.com \
--cc=arnd@arndb.de \
--cc=benh@kernel.crashing.org \
--cc=bsingharora@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=kvm-ppc@vger.kernel.org \
--cc=leonardo@linux.ibm.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mahesh@linux.vnet.ibm.com \
--cc=mpe@ellerman.id.au \
--cc=msuchanek@suse.de \
--cc=npiggin@gmail.com \
--cc=paulus@samba.org \
--cc=robin.murphy@arm.com \
--cc=rppt@linux.ibm.com \
--cc=steven.price@arm.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).