From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tiejun Chen Subject: [v4][PATCH 02/19] xen/x86/p2m: introduce set_identity_p2m_entry Date: Tue, 23 Jun 2015 17:57:13 +0800 Message-ID: <1435053450-25131-3-git-send-email-tiejun.chen@intel.com> References: <1435053450-25131-1-git-send-email-tiejun.chen@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1435053450-25131-1-git-send-email-tiejun.chen@intel.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: Keir Fraser , Tim Deegan , Jan Beulich , Andrew Cooper List-Id: xen-devel@lists.xenproject.org We will create this sort of identity mapping as follows: If the gfn space is unoccupied, we just set the mapping. If space is already occupied by desired identity mapping, do nothing. Otherwise, failure is returned. And we also add a returning value to guest_physmap_remove_page() then make that as a better helper to clear such a p2m entry. CC: Tim Deegan CC: Keir Fraser CC: Jan Beulich CC: Andrew Cooper Signed-off-by: Tiejun Chen Reviewed-by: Kevin Tian --- v4: * Change that orginal condition, if ( p2mt == p2m_invalid || p2mt == p2m_mmio_dm ) to make sure we catch those invalid mfn mapping as we expected. * To have if ( !paging_mode_translate(p2m->domain) ) return 0; at the start, instead of indenting the whole body of the function in an inner scope. * extend guest_physmap_remove_page() to return a value as a proper unmapping helper xen/arch/x86/mm/p2m.c | 40 ++++++++++++++++++++++++++++++++++++++-- xen/include/asm-x86/p2m.h | 10 +++++++--- 2 files changed, 45 insertions(+), 5 deletions(-) diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c index 1fd1194..7e50db6 100644 --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -584,14 +584,16 @@ p2m_remove_page(struct p2m_domain *p2m, unsigned long gfn, unsigned long mfn, p2m->default_access); } -void +int guest_physmap_remove_page(struct domain *d, unsigned long gfn, unsigned long mfn, unsigned int page_order) { struct p2m_domain *p2m = p2m_get_hostp2m(d); + int rc; gfn_lock(p2m, gfn, page_order); - p2m_remove_page(p2m, gfn, mfn, page_order); + rc = p2m_remove_page(p2m, gfn, mfn, page_order); gfn_unlock(p2m, gfn, page_order); + return rc; } int @@ -898,6 +900,40 @@ int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn, return set_typed_p2m_entry(d, gfn, mfn, p2m_mmio_direct, access); } +int set_identity_p2m_entry(struct domain *d, unsigned long gfn, + p2m_access_t p2ma) +{ + p2m_type_t p2mt; + p2m_access_t a; + mfn_t mfn; + struct p2m_domain *p2m = p2m_get_hostp2m(d); + int ret; + + if ( !paging_mode_translate(p2m->domain) ) + return 0; + + gfn_lock(p2m, gfn, 0); + + mfn = p2m->get_entry(p2m, gfn, &p2mt, &a, 0, NULL); + + if ( p2mt == p2m_invalid || p2mt == p2m_mmio_dm ) + ret = p2m_set_entry(p2m, gfn, _mfn(gfn), PAGE_ORDER_4K, + p2m_mmio_direct, p2ma); + else if ( mfn_x(mfn) == gfn && p2mt == p2m_mmio_direct && a == p2ma ) + ret = 0; + else + { + ret = -EBUSY; + printk(XENLOG_G_WARNING + "Cannot setup identity map d%d:%lx," + " gfn already mapped to %lx.\n", + d->domain_id, gfn, mfn_x(mfn)); + } + + gfn_unlock(p2m, gfn, 0); + return ret; +} + /* Returns: 0 for success, -errno for failure */ int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn) { diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h index b49c09b..538a1cf 100644 --- a/xen/include/asm-x86/p2m.h +++ b/xen/include/asm-x86/p2m.h @@ -503,9 +503,9 @@ static inline int guest_physmap_add_page(struct domain *d, } /* Remove a page from a domain's p2m table */ -void guest_physmap_remove_page(struct domain *d, - unsigned long gfn, - unsigned long mfn, unsigned int page_order); +int guest_physmap_remove_page(struct domain *d, + unsigned long gfn, + unsigned long mfn, unsigned int page_order); /* Set a p2m range as populate-on-demand */ int guest_physmap_mark_populate_on_demand(struct domain *d, unsigned long gfn, @@ -543,6 +543,10 @@ int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn, p2m_access_t access); int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn); +/* Set identity addresses in the p2m table (for pass-through) */ +int set_identity_p2m_entry(struct domain *d, unsigned long gfn, + p2m_access_t p2ma); + /* Add foreign mapping to the guest's p2m table. */ int p2m_add_foreign(struct domain *tdom, unsigned long fgfn, unsigned long gpfn, domid_t foreign_domid); -- 1.9.1