From: Alexandru Stefan ISAILA <aisaila@bitdefender.com>
To: Tamas K Lengyel <tamas@tklengyel.com>
Cc: "wei.liu2@citrix.com" <wei.liu2@citrix.com>,
"rcojocaru@bitdefender.com" <rcojocaru@bitdefender.com>,
"george.dunlap@eu.citrix.com" <george.dunlap@eu.citrix.com>,
"andrew.cooper3@citrix.com" <andrew.cooper3@citrix.com>,
"jbeulich@suse.com" <jbeulich@suse.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"roger.pau@citrix.com" <roger.pau@citrix.com>
Subject: Re: [PATCH v3 1/3] x86/mm: Introduce altp2m_get_gfn_type_access
Date: Tue, 9 Apr 2019 14:03:30 +0000 [thread overview]
Message-ID: <d01821fb-f68d-1816-21c4-4d77cb4b7cb6@bitdefender.com> (raw)
In-Reply-To: <CABfawhmyTGNmLP5=c5pWeUiRaSPpwUUw_9SjXoJPr2ZANep41w@mail.gmail.com>
On 09.04.2019 16:48, Tamas K Lengyel wrote:
> On Tue, Apr 9, 2019 at 6:04 AM Alexandru Stefan ISAILA
> <aisaila@bitdefender.com> wrote:
>>
>> This patch moves common code from p2m_set_altp2m_mem_access() and
>> p2m_change_altp2m_gfn() into one function
>>
>> Signed-off-by: Alexandru Isaila <aisaila@bitdefender.com>
>>
>> ---
>> Changes since V2:
>> - Change var name from found_in_hostp2m to copied_from_hostp2m
>> - Move the type check from altp2m_get_gfn_type_access() to the
>> callers.
>> ---
>> xen/arch/x86/mm/mem_access.c | 32 ++++++++++++----------------
>> xen/arch/x86/mm/p2m.c | 41 ++++++++++++++----------------------
>> xen/include/asm-x86/p2m.h | 19 +++++++++++++++++
>> 3 files changed, 49 insertions(+), 43 deletions(-)
>>
>> diff --git a/xen/arch/x86/mm/mem_access.c b/xen/arch/x86/mm/mem_access.c
>> index 56c06a4fc6..bf67ddb15a 100644
>> --- a/xen/arch/x86/mm/mem_access.c
>> +++ b/xen/arch/x86/mm/mem_access.c
>> @@ -265,31 +265,27 @@ int p2m_set_altp2m_mem_access(struct domain *d, struct p2m_domain *hp2m,
>> unsigned int page_order;
>> unsigned long gfn_l = gfn_x(gfn);
>> int rc;
>> + bool copied_from_hostp2m;
>>
>> - mfn = ap2m->get_entry(ap2m, gfn, &t, &old_a, 0, NULL, NULL);
>> + mfn = altp2m_get_gfn_type_access(ap2m, gfn, &t, &old_a, &page_order, &copied_from_hostp2m);
>>
>> - /* Check host p2m if no valid entry in alternate */
>> if ( !mfn_valid(mfn) )
>> + return -ESRCH;
>> +
>> + /* If this is a superpage, copy that first */
>> + if ( page_order != PAGE_ORDER_4K && copied_from_hostp2m )
>> {
>> + unsigned long mask = ~((1UL << page_order) - 1);
>> + gfn_t gfn2 = _gfn(gfn_l & mask);
>> + mfn_t mfn2 = _mfn(mfn_x(mfn) & mask);
>>
>> - mfn = __get_gfn_type_access(hp2m, gfn_l, &t, &old_a,
>> - P2M_ALLOC | P2M_UNSHARE, &page_order, 0);
>> + /* Note: currently it is not safe to remap to a shared entry */
>> + if ( t != p2m_ram_rw )
>> + return -ESRCH;
>>
>> - rc = -ESRCH;
>> - if ( !mfn_valid(mfn) || t != p2m_ram_rw )
>> + rc = ap2m->set_entry(ap2m, gfn2, mfn2, page_order, t, old_a, 1);
>> + if ( rc )
>> return rc;
>> -
>> - /* If this is a superpage, copy that first */
>> - if ( page_order != PAGE_ORDER_4K )
>> - {
>> - unsigned long mask = ~((1UL << page_order) - 1);
>> - gfn_t gfn2 = _gfn(gfn_l & mask);
>> - mfn_t mfn2 = _mfn(mfn_x(mfn) & mask);
>> -
>> - rc = ap2m->set_entry(ap2m, gfn2, mfn2, page_order, t, old_a, 1);
>> - if ( rc )
>> - return rc;
>> - }
>> }
>>
>> /*
>> diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
>> index b9bbb8f485..d38d7c29ca 100644
>> --- a/xen/arch/x86/mm/p2m.c
>> +++ b/xen/arch/x86/mm/p2m.c
>> @@ -2626,6 +2626,7 @@ int p2m_change_altp2m_gfn(struct domain *d, unsigned int idx,
>> mfn_t mfn;
>> unsigned int page_order;
>> int rc = -EINVAL;
>> + bool copied_from_hostp2m;
>>
>> if ( idx >= MAX_ALTP2M || d->arch.altp2m_eptp[idx] == mfn_x(INVALID_MFN) )
>> return rc;
>> @@ -2636,7 +2637,7 @@ int p2m_change_altp2m_gfn(struct domain *d, unsigned int idx,
>> p2m_lock(hp2m);
>> p2m_lock(ap2m);
>>
>> - mfn = ap2m->get_entry(ap2m, old_gfn, &t, &a, 0, NULL, NULL);
>> + mfn = altp2m_get_gfn_type_access(ap2m, old_gfn, &t, &a, &page_order, &copied_from_hostp2m);
>>
>> if ( gfn_eq(new_gfn, INVALID_GFN) )
>> {
>> @@ -2646,37 +2647,27 @@ int p2m_change_altp2m_gfn(struct domain *d, unsigned int idx,
>> goto out;
>> }
>>
>> - /* Check host p2m if no valid entry in alternate */
>> - if ( !mfn_valid(mfn) )
>> - {
>> - mfn = __get_gfn_type_access(hp2m, gfn_x(old_gfn), &t, &a,
>> - P2M_ALLOC, &page_order, 0);
>> + if ( !mfn_valid(mfn) || (t != p2m_ram_rw && copied_from_hostp2m) )
>
> Is this check correct? Why do you want to get out only when type is
> non-rw *and* it's copied from the hostp2m? You could have non-rw
> entries like mmio in the altp2m that were lazily copied and I don't
> think we want to allow remapping to those either.
I just copied the functionality. If this is needed I will add a || t !=
p2m_mmio_dm and p2m_mmio_direct.
Alex
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WARNING: multiple messages have this Message-ID (diff)
From: Alexandru Stefan ISAILA <aisaila@bitdefender.com>
To: Tamas K Lengyel <tamas@tklengyel.com>
Cc: "wei.liu2@citrix.com" <wei.liu2@citrix.com>,
"rcojocaru@bitdefender.com" <rcojocaru@bitdefender.com>,
"george.dunlap@eu.citrix.com" <george.dunlap@eu.citrix.com>,
"andrew.cooper3@citrix.com" <andrew.cooper3@citrix.com>,
"jbeulich@suse.com" <jbeulich@suse.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"roger.pau@citrix.com" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH v3 1/3] x86/mm: Introduce altp2m_get_gfn_type_access
Date: Tue, 9 Apr 2019 14:03:30 +0000 [thread overview]
Message-ID: <d01821fb-f68d-1816-21c4-4d77cb4b7cb6@bitdefender.com> (raw)
Message-ID: <20190409140330.jai6A5URrcSTaM-nKjQeN_MVaqoGVZtffEQoNl8UI80@z> (raw)
In-Reply-To: <CABfawhmyTGNmLP5=c5pWeUiRaSPpwUUw_9SjXoJPr2ZANep41w@mail.gmail.com>
On 09.04.2019 16:48, Tamas K Lengyel wrote:
> On Tue, Apr 9, 2019 at 6:04 AM Alexandru Stefan ISAILA
> <aisaila@bitdefender.com> wrote:
>>
>> This patch moves common code from p2m_set_altp2m_mem_access() and
>> p2m_change_altp2m_gfn() into one function
>>
>> Signed-off-by: Alexandru Isaila <aisaila@bitdefender.com>
>>
>> ---
>> Changes since V2:
>> - Change var name from found_in_hostp2m to copied_from_hostp2m
>> - Move the type check from altp2m_get_gfn_type_access() to the
>> callers.
>> ---
>> xen/arch/x86/mm/mem_access.c | 32 ++++++++++++----------------
>> xen/arch/x86/mm/p2m.c | 41 ++++++++++++++----------------------
>> xen/include/asm-x86/p2m.h | 19 +++++++++++++++++
>> 3 files changed, 49 insertions(+), 43 deletions(-)
>>
>> diff --git a/xen/arch/x86/mm/mem_access.c b/xen/arch/x86/mm/mem_access.c
>> index 56c06a4fc6..bf67ddb15a 100644
>> --- a/xen/arch/x86/mm/mem_access.c
>> +++ b/xen/arch/x86/mm/mem_access.c
>> @@ -265,31 +265,27 @@ int p2m_set_altp2m_mem_access(struct domain *d, struct p2m_domain *hp2m,
>> unsigned int page_order;
>> unsigned long gfn_l = gfn_x(gfn);
>> int rc;
>> + bool copied_from_hostp2m;
>>
>> - mfn = ap2m->get_entry(ap2m, gfn, &t, &old_a, 0, NULL, NULL);
>> + mfn = altp2m_get_gfn_type_access(ap2m, gfn, &t, &old_a, &page_order, &copied_from_hostp2m);
>>
>> - /* Check host p2m if no valid entry in alternate */
>> if ( !mfn_valid(mfn) )
>> + return -ESRCH;
>> +
>> + /* If this is a superpage, copy that first */
>> + if ( page_order != PAGE_ORDER_4K && copied_from_hostp2m )
>> {
>> + unsigned long mask = ~((1UL << page_order) - 1);
>> + gfn_t gfn2 = _gfn(gfn_l & mask);
>> + mfn_t mfn2 = _mfn(mfn_x(mfn) & mask);
>>
>> - mfn = __get_gfn_type_access(hp2m, gfn_l, &t, &old_a,
>> - P2M_ALLOC | P2M_UNSHARE, &page_order, 0);
>> + /* Note: currently it is not safe to remap to a shared entry */
>> + if ( t != p2m_ram_rw )
>> + return -ESRCH;
>>
>> - rc = -ESRCH;
>> - if ( !mfn_valid(mfn) || t != p2m_ram_rw )
>> + rc = ap2m->set_entry(ap2m, gfn2, mfn2, page_order, t, old_a, 1);
>> + if ( rc )
>> return rc;
>> -
>> - /* If this is a superpage, copy that first */
>> - if ( page_order != PAGE_ORDER_4K )
>> - {
>> - unsigned long mask = ~((1UL << page_order) - 1);
>> - gfn_t gfn2 = _gfn(gfn_l & mask);
>> - mfn_t mfn2 = _mfn(mfn_x(mfn) & mask);
>> -
>> - rc = ap2m->set_entry(ap2m, gfn2, mfn2, page_order, t, old_a, 1);
>> - if ( rc )
>> - return rc;
>> - }
>> }
>>
>> /*
>> diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
>> index b9bbb8f485..d38d7c29ca 100644
>> --- a/xen/arch/x86/mm/p2m.c
>> +++ b/xen/arch/x86/mm/p2m.c
>> @@ -2626,6 +2626,7 @@ int p2m_change_altp2m_gfn(struct domain *d, unsigned int idx,
>> mfn_t mfn;
>> unsigned int page_order;
>> int rc = -EINVAL;
>> + bool copied_from_hostp2m;
>>
>> if ( idx >= MAX_ALTP2M || d->arch.altp2m_eptp[idx] == mfn_x(INVALID_MFN) )
>> return rc;
>> @@ -2636,7 +2637,7 @@ int p2m_change_altp2m_gfn(struct domain *d, unsigned int idx,
>> p2m_lock(hp2m);
>> p2m_lock(ap2m);
>>
>> - mfn = ap2m->get_entry(ap2m, old_gfn, &t, &a, 0, NULL, NULL);
>> + mfn = altp2m_get_gfn_type_access(ap2m, old_gfn, &t, &a, &page_order, &copied_from_hostp2m);
>>
>> if ( gfn_eq(new_gfn, INVALID_GFN) )
>> {
>> @@ -2646,37 +2647,27 @@ int p2m_change_altp2m_gfn(struct domain *d, unsigned int idx,
>> goto out;
>> }
>>
>> - /* Check host p2m if no valid entry in alternate */
>> - if ( !mfn_valid(mfn) )
>> - {
>> - mfn = __get_gfn_type_access(hp2m, gfn_x(old_gfn), &t, &a,
>> - P2M_ALLOC, &page_order, 0);
>> + if ( !mfn_valid(mfn) || (t != p2m_ram_rw && copied_from_hostp2m) )
>
> Is this check correct? Why do you want to get out only when type is
> non-rw *and* it's copied from the hostp2m? You could have non-rw
> entries like mmio in the altp2m that were lazily copied and I don't
> think we want to allow remapping to those either.
I just copied the functionality. If this is needed I will add a || t !=
p2m_mmio_dm and p2m_mmio_direct.
Alex
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Xen-devel@lists.xenproject.org
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next prev parent reply other threads:[~2019-04-09 14:03 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-09 12:03 [PATCH v3 1/3] x86/mm: Introduce altp2m_get_gfn_type_access Alexandru Stefan ISAILA
2019-04-09 12:03 ` [Xen-devel] " Alexandru Stefan ISAILA
2019-04-09 12:03 ` [PATCH v3 2/3] x86/mm: Introduce altp2m_set_entry_by_page_order Alexandru Stefan ISAILA
2019-04-09 12:03 ` [Xen-devel] " Alexandru Stefan ISAILA
2019-04-09 13:44 ` Tamas K Lengyel
2019-04-09 13:44 ` [Xen-devel] " Tamas K Lengyel
2019-04-10 14:18 ` George Dunlap
2019-04-10 14:18 ` [Xen-devel] " George Dunlap
2019-04-10 14:22 ` Alexandru Stefan ISAILA
2019-04-10 14:22 ` [Xen-devel] " Alexandru Stefan ISAILA
2019-05-02 14:46 ` Jan Beulich
2019-05-02 14:46 ` [Xen-devel] " Jan Beulich
2019-04-09 12:04 ` [PATCH v3 3/3] x86/mm: Fix p2m_set_suppress_ve Alexandru Stefan ISAILA
2019-04-09 12:04 ` [Xen-devel] " Alexandru Stefan ISAILA
2019-04-09 13:48 ` [PATCH v3 1/3] x86/mm: Introduce altp2m_get_gfn_type_access Tamas K Lengyel
2019-04-09 13:48 ` [Xen-devel] " Tamas K Lengyel
2019-04-09 14:03 ` Alexandru Stefan ISAILA [this message]
2019-04-09 14:03 ` Alexandru Stefan ISAILA
2019-04-09 14:37 ` Tamas K Lengyel
2019-04-09 14:37 ` [Xen-devel] " Tamas K Lengyel
2019-04-09 14:48 ` Alexandru Stefan ISAILA
2019-04-09 14:48 ` [Xen-devel] " Alexandru Stefan ISAILA
2019-04-09 15:26 ` Tamas K Lengyel
2019-04-09 15:26 ` [Xen-devel] " Tamas K Lengyel
2019-04-09 15:37 ` Alexandru Stefan ISAILA
2019-04-09 15:37 ` [Xen-devel] " Alexandru Stefan ISAILA
2019-04-10 16:02 ` George Dunlap
2019-04-10 16:02 ` [Xen-devel] " George Dunlap
2019-04-11 12:17 ` Alexandru Stefan ISAILA
2019-04-11 12:17 ` [Xen-devel] " Alexandru Stefan ISAILA
2019-04-11 12:50 ` George Dunlap
2019-04-11 12:50 ` [Xen-devel] " George Dunlap
2019-04-11 13:28 ` Tamas K Lengyel
2019-04-11 13:28 ` [Xen-devel] " Tamas K Lengyel
2019-04-12 10:59 ` Alexandru Stefan ISAILA
2019-04-12 10:59 ` [Xen-devel] " Alexandru Stefan ISAILA
2019-05-02 14:43 ` Jan Beulich
2019-05-02 14:43 ` [Xen-devel] " Jan Beulich
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