From: Christoph Hellwig <hch@lst.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>, Dexuan Cui <decui@microsoft.com>,
vkuznets <vkuznets@redhat.com>,
Stephen Hemminger <stephen@networkplumber.org>,
Andy Lutomirski <luto@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Michael Kelley <mikelley@microsoft.com>,
Ju-Hyoung Lee <juhlee@microsoft.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
KY Srinivasan <kys@microsoft.com>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: hv_hypercall_pg page permissios
Date: Tue, 16 Jun 2020 12:33:13 +0200 [thread overview]
Message-ID: <20200616103313.GA30833@lst.de> (raw)
In-Reply-To: <20200616103137.GQ2531@hirez.programming.kicks-ass.net>
On Tue, Jun 16, 2020 at 12:31:37PM +0200, Peter Zijlstra wrote:
> On Tue, Jun 16, 2020 at 12:24:12PM +0200, Christoph Hellwig wrote:
> > On Tue, Jun 16, 2020 at 12:23:50PM +0200, Christoph Hellwig wrote:
>
> > > > + hv_hypercall_pg = module_alloc(PAGE_SIZE);
> > > > if (hv_hypercall_pg == NULL) {
> > > > wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
> > > > goto remove_cpuhp_state;
> > > > }
> > > >
> > > > + set_memory_ro((unsigned long)hv_hypercall_pg, 1);
> > > > + set_memory_x((unsigned long)hv_hypercall_pg, 1);
> > >
> > > The changing of the permissions sucks. I thought about adding
> > > a module_alloc_prot with an explicit pgprot_t argument. On x86
> > > alone at least ftrace would also benefit from that.
>
> How would ftrace benefit from a RX permission? We need to actually write
> to the page first. This HV thing is special in that it lets the host
> write.
sorry, s/ftrace/kprobes/. See my updated branch here:
http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/module_alloc-cleanup
next prev parent reply other threads:[~2020-06-16 10:33 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-07 6:55 hv_hypercall_pg page permissios Christoph Hellwig
2020-04-07 7:28 ` Vitaly Kuznetsov
2020-04-07 7:38 ` Christoph Hellwig
2020-04-07 21:01 ` Andy Lutomirski
2020-06-12 7:48 ` Dexuan Cui
2020-06-15 8:35 ` Vitaly Kuznetsov
2020-06-15 17:41 ` Dexuan Cui
2020-06-15 19:49 ` Dexuan Cui
2020-06-16 7:23 ` Christoph Hellwig
2020-06-16 10:18 ` Peter Zijlstra
2020-06-16 10:23 ` Christoph Hellwig
2020-06-16 10:24 ` Christoph Hellwig
2020-06-16 10:31 ` Peter Zijlstra
2020-06-16 10:33 ` Christoph Hellwig [this message]
2020-06-16 10:40 ` Peter Zijlstra
2020-06-16 10:42 ` Christoph Hellwig
2020-06-16 10:52 ` Christoph Hellwig
2020-06-16 11:24 ` Peter Zijlstra
2020-06-16 14:39 ` Christoph Hellwig
2020-06-16 9:29 ` Vitaly Kuznetsov
2020-06-16 9:33 ` Christoph Hellwig
2020-06-16 9:55 ` Christoph Hellwig
2020-06-16 10:08 ` Christoph Hellwig
2020-06-16 10:50 ` Vitaly Kuznetsov
2020-06-16 10:20 ` Peter Zijlstra
2020-04-07 18:10 ` Dexuan Cui
2020-04-07 20:42 ` Wei Liu
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