From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chen, Tiejun" Subject: Re: [v6][PATCH 1/2] xen:x86:mm:p2m: introduce set_identity_p2m_entry Date: Fri, 01 Aug 2014 10:25:43 +0800 Message-ID: <53DAFAA7.90801@intel.com> References: <1406684186-12788-1-git-send-email-tiejun.chen@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Tian, Kevin" , "JBeulich@suse.com" , "Zhang, Yang Z" Cc: "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On 2014/8/1 6:29, Tian, Kevin wrote: >> From: Chen, Tiejun >> Sent: Tuesday, July 29, 2014 6:36 PM >> >> Its used conveniently to create RMRR mapping in shared EPT case. >> >> Signed-off-by: Tiejun Chen >> --- >> xen/arch/x86/mm/p2m.c | 29 +++++++++++++++++++++++++++++ >> xen/include/asm-x86/p2m.h | 3 +++ >> 2 files changed, 32 insertions(+) >> >> v6: >> >> * Refactor set_identity_p2m_entry to make sense >> >> v5: >> >> * Rename this function as set_identity_p2m_entry() >> * Get mfn directly inside set_identity_p2m_entry() >> >> v4: >> >> * new patch to combine get and set together to create RMRR mapping. >> >> diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c >> index 642ec28..06bed7a 100644 >> --- a/xen/arch/x86/mm/p2m.c >> +++ b/xen/arch/x86/mm/p2m.c >> @@ -858,6 +858,35 @@ 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); >> } >> >> +int set_identity_p2m_entry(struct domain *d, unsigned long gfn) >> +{ >> + p2m_type_t p2mt; >> + p2m_access_t a; >> + mfn_t mfn; >> + struct p2m_domain *p2m = p2m_get_hostp2m(d); >> + int ret = -EBUSY; >> + >> + gfn_lock(p2m, gfn, 0); >> + >> + mfn = p2m->get_entry(p2m, gfn, &p2mt, &a, 0, NULL); >> + >> + if ( !mfn_valid(mfn) ) >> + ret = p2m_set_entry(p2m, gfn, _mfn(gfn), PAGE_ORDER_4K, >> p2m_mmio_direct, >> + p2m_access_rw); >> + else if ( mfn_x(mfn) == gfn && >> + p2mt == p2m_mmio_direct && >> + a == p2m_access_rw ) >> + ret = 0; >> + else >> + printk(XENLOG_G_WARNING >> + "Cannot identity map d%d:%lx, already mapped to %lx.\n", >> + d->domain_id, gfn, mfn_x(mfn)); > > what about !mfn_valid but the GFN has been used for emulated MMIOs? w/o > a guest e820 view you can't avoid overlapping by just looking at mfn... What about the follows based on this patch? @@ -865,14 +865,26 @@ int set_identity_p2m_entry(struct domain *d, unsigned long gfn) mfn_t mfn; struct p2m_domain *p2m = p2m_get_hostp2m(d); int ret = -EBUSY; + u64 base_addr, end_addr; gfn_lock(p2m, gfn, 0); mfn = p2m->get_entry(p2m, gfn, &p2mt, &a, 0, NULL); if ( !mfn_valid(mfn) ) + { + base_addr = gfn << PAGE_ORDER_4K; + end_addr = base_addr + PAGE_MASK; + if ( (!page_is_ram_type(paddr_to_pfn(base_addr), RAM_TYPE_RESERVED)) || + (!page_is_ram_type(paddr_to_pfn(end_add), RAM_TYPE_RESERVED)) ) + { + gfn_unlock(p2m, gfn, 0); + return ret; + } + ret = p2m_set_entry(p2m, gfn, _mfn(gfn), PAGE_ORDER_4K, p2m_mmio_direct, p2m_access_rw); + } else if ( mfn_x(mfn) == gfn && p2mt == p2m_mmio_direct && a == p2m_access_rw ) Note this chunk of codes just show what I want to do, without test. Thanks Tiejun > > Thanks > Kevin > >> + >> + 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) >> { >> diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h >> index 0ddbadb..d130f9a 100644 >> --- a/xen/include/asm-x86/p2m.h >> +++ b/xen/include/asm-x86/p2m.h >> @@ -536,6 +536,9 @@ int p2m_is_logdirty_range(struct p2m_domain *, >> unsigned long start, >> int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn); >> int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn); >> >> +/* Set identity addresses in the p2m table (for pass-through) */ >> +int set_identity_p2m_entry(struct domain *d, unsigned long gfn); >> + >> /* 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 > >