From patchwork Wed Sep 25 15:01:01 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 13812148 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9DEC14644E for ; Wed, 25 Sep 2024 15:01:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727276517; cv=none; b=tpuchocB+IAfAvymqanMgri6nknUTgyYyqkebtc5FV+6GJBXSvXvYHICersRPlXV4cGjeAro1dlb8r0IDe4hPREdjrHF6+ZcrckVobFX/86S5z1p4wm4tIYGq5riK5mQjnz0vr1A6poqIZDQxF/mPFlNhaLejNEEJeL6DCIxuok= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727276517; c=relaxed/simple; bh=7J0jWEjwrexzo9oPbBgZ33ZQC1xyFpo8+XmzUWJ/VHg=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=a7g+QVQkU6uW0agYqZKYP9+OPFfersf91iK/L67CpCMMt4hVxn7ikYHniPCXC2Bdvpu3QWVoBXsiH1prtcKL+Zbr9itJB2RUTzRfcvN/zJEYb2Q7JCRySuLFOwc9uI7WV3ifJlsgb9lhwbZkVMvT0oTzOT3HaSnFQ55ThQAT5Gg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=yEqqSHTi; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="yEqqSHTi" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-42e611963c2so45772215e9.1 for ; Wed, 25 Sep 2024 08:01:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1727276512; x=1727881312; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=bvHrMBM7osvq1YNoyXkrrTpmrTIb8bNW96uzrIXNQu8=; b=yEqqSHTileV8mRFw/uWhSlHf8HPvgLYHAzC0BoLZiiRPC+JG3TnSCk/wzr0FcVCQ4C u1wy8geYYzk+k4fHyl0oA//q+pNRtKEVT0HoK/m1g7ACiBEhqCqS7nfz/jBUWb10ZUrv gQHVZ3OYRmXq4n1p6xDqyQVOury3bDN40Tm7ZUTsfao/pHE9eY6s3wdLgrHqAipLGuHU HazsPfuHo6iAIwTZzdr3uqUJRMvzHVWSm9Mtyt29amKKtthr4fq4j66MH5FvyNglmzG5 PANRA3J72y8uR8mXzuGElRpueMNhdk3AB8ci0000K0KiLGQ3Pdy3CtmRJ5FM1N7rpZGA SXtw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727276512; x=1727881312; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=bvHrMBM7osvq1YNoyXkrrTpmrTIb8bNW96uzrIXNQu8=; b=PwvJjTqoT3IWGZyztn6wdHX5sj9fEkpRI9UKWaAggaHJo58YjvqMie5JqwgiEiqqDN YaqUzbvHEWao5KhDSzRWP8Rdj21qp/bZQmRH8XcoVAWccY1aiFFctgBOVYMWcV+FarV9 JRzK93gBVcjDEp/C2xnN7r1Sq4Foe2CME9QV80vUwWP/Dg1qsrMiAeufoEZoUUWo6zbN P7deIW7tnTNZGyiWi6DnGtusRH58vT3kVJKXhuBNOTAQTVGG3yqjdpeGeggeMx2H/meK 2Tk84UukRCX0vvAp7dectA2aaYuCI+G596YyphpwVT2kRL0Nv7pbdHW9L5mPBBkrtV9M jkxA== X-Forwarded-Encrypted: i=1; AJvYcCV+6gntuv7o1mjZahvxWsnuWe+z9jM6TY3stHRCKFc7dX48DP2qhYAs9swpOpFV3ie+DpB4qgWIiZeJHgY=@vger.kernel.org X-Gm-Message-State: AOJu0YzHUhSopSWmg3a1zpv5pqPOf9bVyXA3Kf5PWmNiCyzHjxuX3/BK /4LQOdf7zvQHCrCFh2/AKTzoX10Sd3xz7BFSz9tTLyJs5WMABjqS2g9nADETDOlzeScv5w== X-Google-Smtp-Source: AGHT+IGNEZwim//wtoUQ0IgEwXQAmuWMXuvjVNrkXztiUbXuSVle0sf2azOpfGly/wGUuNh4kSi9g764 X-Received: from palermo.c.googlers.com ([fda3:e722:ac3:cc00:7b:198d:ac11:8138]) (user=ardb job=sendgmr) by 2002:a05:600c:4b23:b0:42c:b635:9ba7 with SMTP id 5b1f17b1804b1-42e961449f9mr294105e9.3.1727276511763; Wed, 25 Sep 2024 08:01:51 -0700 (PDT) Date: Wed, 25 Sep 2024 17:01:01 +0200 In-Reply-To: <20240925150059.3955569-30-ardb+git@google.com> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240925150059.3955569-30-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=1383; i=ardb@kernel.org; h=from:subject; bh=kkus52hb+9U3rGqLGvcTtWiqi7ULiH1wdI2hpFI7/9I=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIe2L6loPG1eTz6/TRZ+ExF55v9yoPVaMz0DJP05TXvNix 3yvWS87SlkYxDgYZMUUWQRm/3238/REqVrnWbIwc1iZQIYwcHEKwER0vzAyLNdk+Hf0DcN93e0c kou2iV0ReKfEPrsn3ORh04fsoM3R+gz/0yZt5ne4cnJFldTMQpGfLor75ZYczDujFLCs+4iee6Q pMwA= X-Mailer: git-send-email 2.46.0.792.g87dc391469-goog Message-ID: <20240925150059.3955569-31-ardb+git@google.com> Subject: [RFC PATCH 01/28] x86/pvh: Call C code via the kernel virtual mapping From: Ard Biesheuvel To: linux-kernel@vger.kernel.org Cc: Ard Biesheuvel , x86@kernel.org, "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Uros Bizjak , Dennis Zhou , Tejun Heo , Christoph Lameter , Mathieu Desnoyers , Paolo Bonzini , Vitaly Kuznetsov , Juergen Gross , Boris Ostrovsky , Greg Kroah-Hartman , Arnd Bergmann , Masahiro Yamada , Kees Cook , Nathan Chancellor , Keith Packard , Justin Stitt , Josh Poimboeuf , Arnaldo Carvalho de Melo , Namhyung Kim , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , linux-doc@vger.kernel.org, linux-pm@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, linux-efi@vger.kernel.org, linux-arch@vger.kernel.org, linux-sparse@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-perf-users@vger.kernel.org, rust-for-linux@vger.kernel.org, llvm@lists.linux.dev From: Ard Biesheuvel Calling C code via a different mapping than it was linked at is problematic, because the compiler assumes that RIP-relative and absolute symbol references are interchangeable. GCC in particular may use RIP-relative per-CPU variable references even when not using -fpic. So call xen_prepare_pvh() via its kernel virtual mapping on x86_64, so that those RIP-relative references produce the correct values. This matches the pre-existing behavior for i386, which also invokes xen_prepare_pvh() via the kernel virtual mapping before invoking startup_32 with paging disabled again. Fixes: 7243b93345f7 ("xen/pvh: Bootstrap PVH guest") Signed-off-by: Ard Biesheuvel Tested-by: Jason Andryuk Reviewed-by: Jason Andryuk --- arch/x86/platform/pvh/head.S | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S index f7235ef87bc3..a308b79a887c 100644 --- a/arch/x86/platform/pvh/head.S +++ b/arch/x86/platform/pvh/head.S @@ -101,7 +101,11 @@ SYM_CODE_START_LOCAL(pvh_start_xen) xor %edx, %edx wrmsr - call xen_prepare_pvh + /* Call xen_prepare_pvh() via the kernel virtual mapping */ + leaq xen_prepare_pvh(%rip), %rax + addq $__START_KERNEL_map, %rax + ANNOTATE_RETPOLINE_SAFE + call *%rax /* startup_64 expects boot_params in %rsi. */ mov $_pa(pvh_bootparams), %rsi