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From: Kai Huang <kai.huang@intel.com>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: linux-sgx@vger.kernel.org, dave.hansen@intel.com,
	haitao.huang@intel.com, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v2 2/2] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()
Date: Thu, 14 Jan 2021 10:40:42 +1300	[thread overview]
Message-ID: <20210114104042.95da8258b2e3f9063ae79aba@intel.com> (raw)
In-Reply-To: <X/9hONWr8c9XLB14@kernel.org>

On Wed, 13 Jan 2021 23:08:08 +0200 Jarkko Sakkinen wrote:
> On Wed, Jan 13, 2021 at 02:09:17PM +1300, Kai Huang wrote:
> > On Wed, 13 Jan 2021 01:33:51 +0200 jarkko@kernel.org wrote:
> > > From: "jarkko@kernel.org" <jarkko@kernel.org>
> > > 
> > > Encapsulate the snippet in sgx_free_epc_page() concerning EREMOVE to
> > > sgx_reset_epc_page(), which is a static helper function for
> > > sgx_encl_release(). It's the only function existing, which deals with
> > > initialized pages.
> > > 
> > > Signed-off-by: jarkko@kernel.org <jarkko@kernel.org>
> > > ---
> > > v2: Fixed a compilation error s/page/epc_page/ change not amended
> > >     to the patches.
> > >  arch/x86/kernel/cpu/sgx/encl.c | 15 ++++++++++++++-
> > >  arch/x86/kernel/cpu/sgx/main.c | 10 ++++------
> > >  2 files changed, 18 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> > > index fe7256db6e73..511f4bc70699 100644
> > > --- a/arch/x86/kernel/cpu/sgx/encl.c
> > > +++ b/arch/x86/kernel/cpu/sgx/encl.c
> > > @@ -389,6 +389,16 @@ const struct vm_operations_struct sgx_vm_ops = {
> > >  	.access = sgx_vma_access,
> > >  };
> > >  
> > > +
> > > +static void sgx_reset_epc_page(struct sgx_epc_page *epc_page)
> > > +{
> > > +	int ret;
> > > +
> > > +	ret = __eremove(sgx_get_epc_virt_addr(epc_page));
> > > +	if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
> > > +		return;
> > > +}
> > > +
> > >  /**
> > >   * sgx_encl_release - Destroy an enclave instance
> > >   * @kref:	address of a kref inside &sgx_encl
> > > @@ -412,6 +422,7 @@ void sgx_encl_release(struct kref *ref)
> > >  			if (sgx_unmark_page_reclaimable(entry->epc_page))
> > >  				continue;
> > >  
> > > +			sgx_reset_epc_page(entry->epc_page);
> > >  			sgx_free_epc_page(entry->epc_page);
> > >  			encl->secs_child_cnt--;
> > >  			entry->epc_page = NULL;
> > > @@ -423,6 +434,7 @@ void sgx_encl_release(struct kref *ref)
> > >  	xa_destroy(&encl->page_array);
> > >  
> > >  	if (!encl->secs_child_cnt && encl->secs.epc_page) {
> > > +		sgx_reset_epc_page(encl->secs.epc_page);
> > >  		sgx_free_epc_page(encl->secs.epc_page);
> > >  		encl->secs.epc_page = NULL;
> > >  	}
> > > @@ -431,7 +443,8 @@ void sgx_encl_release(struct kref *ref)
> > >  		va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
> > >  					   list);
> > >  		list_del(&va_page->list);
> > > -		sgx_free_epc_page(va_page->epc_page);
> > > +		sgx_reset_epc_page(entry->epc_page);
> > > +		sgx_free_epc_page(entry->epc_page);
> > 
> > Reply so that Sean can see, since he just subscribed to linux-sgx list.
> > 
> > As Sean pointed out in KVM SGX virtualization thread, entry should be va_page.
> 
> Thank, noticed, and responded. I'm sending v3. I think it would be best to
> then include that version to KVM patch set, as there is no such a rush to
> get my patches to upstream. I already dropped them from my bleeding edge
> numa branch.

Sure. I'll take your patch once I see it. Thanks Jarkko.


      reply	other threads:[~2021-01-14  2:13 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-12 23:33 [PATCH v2 0/2] Take away EREMOVE from sgx_free_epc_page() jarkko
2021-01-12 23:33 ` [PATCH v2 1/2] x86/sgx: Remove a warn " jarkko
2021-01-12 23:33 ` [PATCH v2 2/2] x86/sgx: Wipe out EREMOVE " jarkko
2021-01-13  1:09   ` Kai Huang
2021-01-13 21:08     ` Jarkko Sakkinen
2021-01-13 21:40       ` Kai Huang [this message]

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