From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arianna Avanzini Subject: [PATCH v4 2/7] arch, arm: add consistency checks to REMOVE p2m changes Date: Tue, 25 Mar 2014 03:02:51 +0100 Message-ID: <1395712976-19454-3-git-send-email-avanzini.arianna@gmail.com> References: <1395712976-19454-1-git-send-email-avanzini.arianna@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1395712976-19454-1-git-send-email-avanzini.arianna@gmail.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: Ian.Campbell@eu.citrix.com, paolo.valente@unimore.it, keir@xen.org, stefano.stabellini@eu.citrix.com, Ian.Jackson@eu.citrix.com, dario.faggioli@citrix.com, tim@xen.org, julien.grall@citrix.com, etrudeau@broadcom.com, JBeulich@suse.com, avanzini.arianna@gmail.com, viktor.kleinik@globallogic.com List-Id: xen-devel@lists.xenproject.org Currently, the REMOVE case of the switch in apply_p2m_changes() does not perform any consistency check on the mapping to be removed. More in detail, the code does not check if the guest address to be unmapped is actually mapped to the machine address given as a parameter. This commit attempts to add the above-described consistency check to the REMOVE path of apply_p2m_changes(). This is instrumental to one of the following commits which implements the possibility to trigger the removal of p2m ranges via the memory_mapping DOMCTL for ARM. Signed-off-by: Arianna Avanzini Cc: Dario Faggioli Cc: Paolo Valente Cc: Stefano Stabellini Cc: Julien Grall Cc: Ian Campbell Cc: Jan Beulich Cc: Keir Fraser Cc: Tim Deegan Cc: Ian Jackson Cc: Eric Trudeau Cc: Viktor Kleinik --- v4: - Remove useless and slow lookup and use already-available data from pte instead. - Correctly increment the local variable used to keep the machine address whose mapping is currently being removed. - Return with an error upon finding a mismatch between the actual machine address mapped to the guest address and the machine address passed as parameter, instead of just skipping the page. --- xen/arch/arm/p2m.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index d00c882..bb0db16 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -243,12 +243,13 @@ static int apply_p2m_changes(struct domain *d, int rc; struct p2m_domain *p2m = &d->arch.p2m; lpae_t *first = NULL, *second = NULL, *third = NULL; - paddr_t addr; + paddr_t addr, _maddr; unsigned long cur_first_page = ~0, cur_first_offset = ~0, cur_second_offset = ~0; unsigned long count = 0; unsigned int flush = 0; + unsigned long mfn; bool_t populate = (op == INSERT || op == ALLOCATE); lpae_t pte; @@ -258,6 +259,7 @@ static int apply_p2m_changes(struct domain *d, p2m_load_VTTBR(d); addr = start_gpaddr; + _maddr = maddr; while ( addr < end_gpaddr ) { if ( cur_first_page != p2m_first_level_index(addr) ) @@ -327,6 +329,7 @@ static int apply_p2m_changes(struct domain *d, flush |= pte.p2m.valid; + mfn = pte.p2m.base; /* TODO: Handle other p2m type * * It's safe to do the put_page here because page_alloc will @@ -335,8 +338,6 @@ static int apply_p2m_changes(struct domain *d, */ if ( pte.p2m.valid && p2m_is_foreign(pte.p2m.type) ) { - unsigned long mfn = pte.p2m.base; - ASSERT(mfn_valid(mfn)); put_page(mfn_to_page(mfn)); } @@ -367,9 +368,23 @@ static int apply_p2m_changes(struct domain *d, maddr += PAGE_SIZE; } break; - case RELINQUISH: case REMOVE: { + ASSERT(pte.p2m.valid); + /* + * Ensure that the guest address given as argument to + * this function is actually mapped to the specified + * machine address. _maddr here is the machine address + * given to the function, while mfn is the machine + * frame number actually mapped to the guest address: + * check if the two correspond. + */ + if ( _maddr != pfn_to_paddr(mfn) ) + return -EINVAL; + } + /* fall through */ + case RELINQUISH: + { if ( !pte.p2m.valid ) { count++; @@ -408,6 +423,7 @@ static int apply_p2m_changes(struct domain *d, /* Got the next page */ addr += PAGE_SIZE; + _maddr += PAGE_SIZE; } if ( flush ) -- 1.9.0