From nobody Wed Nov 27 17:29:16 2024 Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (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 973921E2827 for ; Wed, 9 Oct 2024 16:09:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728490149; cv=none; b=X5PyJpFmvTW4Rcajk50pZUqEWDsij9EdSG6GAF2ign87nXbZ2z0BADVlVlqEtzWCIq+4od/c9Y0rnHeOdbqz3I0o08rHO3gYj8knvbW6WPdzvwOEFlQXmyDLlrlbPGRYLRp44p704ax3GwyvGkuG42kV7SA0yZjYESld0CCF55M= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728490149; c=relaxed/simple; bh=n8f+eWsGmScuFwG5dDubDwigdZfb6CilE2zs5pzESkg=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=KYoBcAXPIAAs5PuKXfDugO2AdjsYP/QkUoqgx8+tdMPhu9FcleL3lhVtv3HPFhQJcAiCMBS+wxLeHSyChY69Bgmaw4Q5bB8Mny8B9om2RFvPjNWhPVTjSe6CHLssvUJGAc2hFLY0Ajv7YWEHCw1QDDCjy2dMZVTpWuABWylOYss= 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=bqxlR1Ad; arc=none smtp.client-ip=209.85.219.201 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="bqxlR1Ad" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-e24a31ad88aso8085729276.1 for ; Wed, 09 Oct 2024 09:09:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1728490146; x=1729094946; 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=N4os8DmpWomyhdXT3uIE5sI0/fikMzrPBJolJZzSSPQ=; b=bqxlR1Adq1QmrIGrbhG/hIoWMB6bVQt03zRRiEYQRfiV/SkYjzltkBUw0eoCJ2JHQS zLf95Z2G3uiGsIQz34XEJX2jalMlOsy4njxoplguna7HHGoZbokOjxD90g3/b4Ioy3yS 4ZrqmetmaYOR+eLlcWPC8wtyl9vizXr8gyEcZbquJPZ79a8acrFYWFyglP2/b+DZNKhe 2cjykuQHE+P3ToS1rTX3SYleJIdwPzpnW+JLBQibH7g2YdmU/FyKY999S1GfcC/3kHDw 3AIqkUEcOMEUbzpNlE3L1LvkzuREKw+uDTn+Ef91Uc5Ox3HduJ32Qe24MOMYwGWpgA6V Zrog== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728490146; x=1729094946; 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=N4os8DmpWomyhdXT3uIE5sI0/fikMzrPBJolJZzSSPQ=; b=Zn1rhkS8/HmdfmR8C1dEIFwdpQVM0V4LirzGsuFemwRLgWUbjL6nJV64fxOjHZkF9R gArwceDpJBJGLv6+ZHE6NpDNgt33+AagxJDmBpqvJLLD8uxz0ztg1Jg0WkZtWq3wRiGC uaqwZGOGzSuTWOcQWCchSwG+K+QgAUDlVOrnCNH66UzqDS98CRQDZx+GQ5sakPojG7cY 3kpDh9aR/Xk44nTpxJrxh381JSyqMUUOnH0hW6tsJS8GeQxGVMv7bHHIwXskz0pUvbin IkTZlShAI1H2nhHVgSYkVkSu69DJy+5ZsB7vzJFl2KHhE+nXvpz2f3CXL+qRAu8VlmkT 2mzw== X-Gm-Message-State: AOJu0Ywcnpwvmswz06UR1KnTTqYTA7w4EXbu+MuS7DZiX/cJi0/kBdTr lmUIBtJNxR7asWw4+lWasSIzolr/HJW/tNSgCHChzKgzOiJIP89eXSDJzxklFiiz4izpSFLM4wo JgJoupxFYDAnuSRWTAMC1RB4le/nk/4ywkjxrsZm6pLQ6W8rjIvGgY2IBpy98PTuHK6NN+y1hfk 6KNHI0v79v3J4/XDD+ryaq838k+RyEIQ== X-Google-Smtp-Source: AGHT+IFT6IBvqDFvd1nh9Nvp19An6mvh9GEkIy5aq6tG0DxKt0GfrpuME+IFqFwS7fy8QSz4NyDyDfDy X-Received: from palermo.c.googlers.com ([fda3:e722:ac3:cc00:7b:198d:ac11:8138]) (user=ardb job=sendgmr) by 2002:a25:850d:0:b0:e25:5cb1:77d8 with SMTP id 3f1490d57ef6-e28fe4edeb1mr2566276.6.1728490146127; Wed, 09 Oct 2024 09:09:06 -0700 (PDT) Date: Wed, 9 Oct 2024 18:04:40 +0200 In-Reply-To: <20241009160438.3884381-7-ardb+git@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241009160438.3884381-7-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=1584; i=ardb@kernel.org; h=from:subject; bh=iWMVWWds+djQXEXyMG9PXtB+asvAc5L9HBTrJQ9xUI0=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIZ1t5Qzb+5vWNIRfeP0j+K0038QHKYoJW6Ocbk1xPSMu9 /ZLNUtyRykLgxgHg6yYIovA7L/vdp6eKFXrPEsWZg4rE8gQBi5OAZjIlByGPzxHlDuFHVdUrt/r MSct7e16de7eyB6v8DvPj7HsC2gs3MrwT9XpV2I1e25o/5H0axwpbNmz58ruzF5mZerQszMwWMW EFwA= X-Mailer: git-send-email 2.47.0.rc0.187.ge670bccf7e-goog Message-ID: <20241009160438.3884381-8-ardb+git@google.com> Subject: [PATCH v3 1/5] x86/pvh: Call C code via the kernel virtual mapping From: Ard Biesheuvel To: linux-kernel@vger.kernel.org Cc: Ard Biesheuvel , Jason Andryuk , Juergen Gross , Boris Ostrovsky , x86@kernel.org, xen-devel@lists.xenproject.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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") Tested-by: Jason Andryuk Reviewed-by: Jason Andryuk Signed-off-by: Ard Biesheuvel --- arch/x86/platform/pvh/head.S | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S index 64fca49cd88f..ce4fd8d33da4 100644 --- a/arch/x86/platform/pvh/head.S +++ b/arch/x86/platform/pvh/head.S @@ -172,7 +172,14 @@ SYM_CODE_START_LOCAL(pvh_start_xen) movq %rbp, %rbx subq $_pa(pvh_start_xen), %rbx movq %rbx, phys_base(%rip) - call xen_prepare_pvh + + /* Call xen_prepare_pvh() via the kernel virtual mapping */ + leaq xen_prepare_pvh(%rip), %rax + subq phys_base(%rip), %rax + addq $__START_KERNEL_map, %rax + ANNOTATE_RETPOLINE_SAFE + call *%rax + /* * Clear phys_base. __startup_64 will *add* to its value, * so reset to 0. --=20 2.47.0.rc0.187.ge670bccf7e-goog