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Tue, 16 Jan 2024 19:26:47 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-Inumbo-ID: 3b08b66f-b4a5-11ee-98f1-6d05b1d4d9a1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1705433227; x=1736969227; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=bXzdRNb+zZSWrMCWDYUPYL1ZiOjiL92dtef2XmbIpMo=; b=Q8AvmtJf4ZsrgXTlelbv8j5FR3wVday9zQQ/PGbrpdid0DMyGTRSNuaJ zXd9J3hXeDYPKB7o5zfpZu/Bu6/IFhUSMSbPwutQbHKToqs9qCfgU2mC3 rPwh6fDrxcRjT+hTCnbRodHB2IbSCkppQUgHc23AZd8nuPU6qBjvk68HV s=; X-IronPort-AV: E=Sophos;i="6.05,200,1701129600"; d="scan'208";a="178399576" X-Farcaster-Flow-ID: 98f57ce2-9333-45bc-9ae3-0f84349af0f9 From: Elias El Yandouzi To: CC: , , , Julien Grall , Andrew Cooper , George Dunlap , Jan Beulich , "Stefano Stabellini" , Wei Liu , Bertrand Marquis , Michal Orzel , "Volodymyr Babchuk" , Elias El Yandouzi Subject: [PATCH v2 (resend) 27/27] xen/arm64: Allow the admin to enable/disable the directmap Date: Tue, 16 Jan 2024 19:26:11 +0000 Message-ID: <20240116192611.41112-28-eliasely@amazon.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240116192611.41112-1-eliasely@amazon.com> References: <20240116192611.41112-1-eliasely@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: Bulk X-ZohoMail-DKIM: pass (identity @amazon.com) X-ZM-MESSAGEID: 1705434021177100001 Content-Type: text/plain; charset="utf-8" From: Julien Grall Implement the same command line option as x86 to enable/disable the directmap. By default this is kept enabled. Also modify setup_directmap_mappings() to populate the L0 entries related to the directmap area. Signed-off-by: Julien Grall Signed-off-by: Elias El Yandouzi ---- Changes in v2: * Rely on the Kconfig option to enable Secret Hiding on Arm64 * Use generic helper instead of arch_has_directmap() diff --git a/docs/misc/xen-command-line.pandoc b/docs/misc/xen-command-line= .pandoc index 63c946f482..df90b1c4c9 100644 --- a/docs/misc/xen-command-line.pandoc +++ b/docs/misc/xen-command-line.pandoc @@ -799,7 +799,7 @@ that enabling this option cannot guarantee anything bey= ond what underlying hardware guarantees (with, where available and known to Xen, respective tweaks applied). =20 -### directmap (x86) +### directmap (arm64, x86) > `=3D ` =20 > Default: `true` diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig index 278243f0d6..7a19826233 100644 --- a/xen/arch/arm/Kconfig +++ b/xen/arch/arm/Kconfig @@ -7,6 +7,7 @@ config ARM_64 depends on !ARM_32 select 64BIT select HAS_FAST_MULTIPLY + select HAS_SECRET_HIDING =20 config ARM def_bool y diff --git a/xen/arch/arm/arm64/mmu/mm.c b/xen/arch/arm/arm64/mmu/mm.c index f4a81aa705..22e1e5b9f4 100644 --- a/xen/arch/arm/arm64/mmu/mm.c +++ b/xen/arch/arm/arm64/mmu/mm.c @@ -157,16 +157,27 @@ void __init switch_ttbr(uint64_t ttbr) update_identity_mapping(false); } =20 -/* Map the region in the directmap area. */ +/* + * This either populate a valid fdirect map, or allocates empty L1 tables + * and creates the L0 entries for the given region in the direct map + * depending on has_directmap(). + * + * When directmap=3Dno, we still need to populate empty L1 tables in the + * directmap region. The reason is that the root page-table (i.e. L0) + * is per-CPU and secondary CPUs will initialize their root page-table + * based on the pCPU0 one. So L0 entries will be shared if they are + * pre-populated. We also rely on the fact that L1 tables are never + * freed. + */ static void __init setup_directmap_mappings(unsigned long base_mfn, unsigned long nr_mfns) { + unsigned long mfn_gb =3D base_mfn & ~((FIRST_SIZE >> PAGE_SHIFT) - 1); int rc; =20 /* First call sets the directmap physical and virtual offset. */ if ( mfn_eq(directmap_mfn_start, INVALID_MFN) ) { - unsigned long mfn_gb =3D base_mfn & ~((FIRST_SIZE >> PAGE_SHIFT) -= 1); =20 directmap_mfn_start =3D _mfn(base_mfn); directmap_base_pdx =3D mfn_to_pdx(_mfn(base_mfn)); @@ -187,6 +198,24 @@ static void __init setup_directmap_mappings(unsigned l= ong base_mfn, panic("cannot add directmap mapping at %lx below heap start %lx\n", base_mfn, mfn_x(directmap_mfn_start)); =20 + if ( !has_directmap() ) + { + vaddr_t vaddr =3D (vaddr_t)__mfn_to_virt(base_mfn); + lpae_t *root =3D this_cpu(xen_pgtable); + unsigned int i, slot; + + slot =3D first_table_offset(vaddr); + nr_mfns +=3D base_mfn - mfn_gb; + for ( i =3D 0; i < nr_mfns; i +=3D BIT(XEN_PT_LEVEL_ORDER(0), UL),= slot++ ) + { + lpae_t *entry =3D &root[slot]; + + if ( !lpae_is_valid(*entry) && !create_xen_table(entry) ) + panic("Unable to populate zeroeth slot %u\n", slot); + } + return; + } + rc =3D map_pages_to_xen((vaddr_t)__mfn_to_virt(base_mfn), _mfn(base_mfn), nr_mfns, PAGE_HYPERVISOR_RW | _PAGE_BLOCK); diff --git a/xen/arch/arm/include/asm/arm64/mm.h b/xen/arch/arm/include/asm= /arm64/mm.h index e0bd23a6ed..5888f29159 100644 --- a/xen/arch/arm/include/asm/arm64/mm.h +++ b/xen/arch/arm/include/asm/arm64/mm.h @@ -3,13 +3,10 @@ =20 extern DEFINE_PAGE_TABLE(xen_pgtable); =20 -/* - * On ARM64, all the RAM is currently direct mapped in Xen. - * Hence return always true. - */ +/* On Arm64, the user can chose whether all the RAM is directmap. */ static inline bool arch_mfns_in_directmap(unsigned long mfn, unsigned long= nr) { - return true; + return has_directmap(); } =20 void arch_setup_page_tables(void); diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c index b15a18a494..7fb75c5c3e 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -12,6 +12,7 @@ #include #include #include +#include =20 #include =20 diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c index 3dec365c57..2bd060d321 100644 --- a/xen/arch/arm/setup.c +++ b/xen/arch/arm/setup.c @@ -748,6 +748,7 @@ void asmlinkage __init start_xen(unsigned long boot_phy= s_offset, cmdline_parse(cmdline); =20 setup_mm(); + printk("Booting with directmap %s\n", has_directmap() ? "on" : "off"); =20 vm_init(); =20 --=20 2.40.1