From patchwork Fri May 28 09:07:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicholas Piggin X-Patchwork-Id: 1485088 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=kvm-ppc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=WZKn3cKN; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4FrzPs0DQcz9t10 for ; Fri, 28 May 2021 19:08:49 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235486AbhE1JKU (ORCPT ); Fri, 28 May 2021 05:10:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45402 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234724AbhE1JJ4 (ORCPT ); Fri, 28 May 2021 05:09:56 -0400 Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A246C061760 for ; Fri, 28 May 2021 02:08:18 -0700 (PDT) Received: by mail-pg1-x52c.google.com with SMTP id 29so2034375pgu.11 for ; Fri, 28 May 2021 02:08:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=c4rb6UpQNet/XLnuaDGUA+A1NAiDLTGDulXgKSIiuFk=; b=WZKn3cKN9MqzwXQMiVYB5hAK8ZyyQ3iJohKTA9ypRCj6URPr8yyZ9yFlSxxrOHAtme 0sU/QYkoiWMoc0RqXqbLZgyCSGPH53tLxRTqzxm7u1S4zF4lhs5m/vWXyWj7dt9lGso0 UTS6Y/Im/oZVQzHTULl7KWZP+dlmrJTdrcuJa80zYnctPlItOe2myNqhZppiiTg8TIM1 a+8QuomCXB+KCC8p2HWz90A/ovnY51ZT9OADyd9Lx2Hcab5pi91U29ozKhxqPK077eph U+cb6uGgL2SOoQ1+Urmetn7hMGeN19L1iKYcsiivXLlWirCTuWGy5BZZg+MAU9ywm9Ly 0OWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=c4rb6UpQNet/XLnuaDGUA+A1NAiDLTGDulXgKSIiuFk=; b=jc9whQcBODF6asePdoLhtsiiKtZOOUCsfxHcp/9MT83S06c6YQYUtxhHOJgJ9183q7 KeAN+WIWp7JE0RlPNTZI3AKwiIpUdfKkVXveUOI42APd/b6UB2PyzIwS8TM03/ParEu/ iHndmFYe3aUhfxwK1WotMZ1xRlSL1fBfqaaPwogUaBaP0GaqbRDurEatp6R59s91DTSm xSLq+3b9Bpwh+Wn0kBjHVBy8rzjwKbb3eh+wr/74zAAlMbSagMumiyGwIsod07Ii8izy 5RNQtttjKO1NhZ5OeOsiM5kH3oSVLKeIUArTPZD6/58FK4k8kxJpWiMfodIWK3AMiPHT 1Txw== X-Gm-Message-State: AOAM531b4cGmEYyGSLcdynKbuBXqzaSLT/LdZc26W6JX0yD8t+TQCfCS 5woDXGO6/NAGUOmg/5rMk9kWo7raxPc= X-Google-Smtp-Source: ABdhPJyURGsf1RMNT6oGeHh+oTVpMtiMaV1QLTJx9CvidU5TSCZAolT/E8rNzStLCzY7gKPiJVmDoA== X-Received: by 2002:a65:564c:: with SMTP id m12mr8167235pgs.298.1622192897543; Fri, 28 May 2021 02:08:17 -0700 (PDT) Received: from bobo.ibm.com (124-169-110-219.tpgi.com.au. [124.169.110.219]) by smtp.gmail.com with ESMTPSA id a2sm3624183pfv.156.2021.05.28.02.08.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 May 2021 02:08:17 -0700 (PDT) From: Nicholas Piggin To: kvm-ppc@vger.kernel.org Cc: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, Alexey Kardashevskiy Subject: [PATCH v7 07/32] KVM: PPC: Book3S 64: Minimise hcall handler calling convention differences Date: Fri, 28 May 2021 19:07:27 +1000 Message-Id: <20210528090752.3542186-8-npiggin@gmail.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20210528090752.3542186-1-npiggin@gmail.com> References: <20210528090752.3542186-1-npiggin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org This sets up the same calling convention from interrupt entry to KVM interrupt handler for system calls as exists for other interrupt types. This is a better API, it uses a save area rather than SPR, and it has more registers free to use. Using a single common API helps maintain it, and it becomes easier to use in C in a later patch. Reviewed-by: Alexey Kardashevskiy Signed-off-by: Nicholas Piggin --- arch/powerpc/kernel/exceptions-64s.S | 21 +++++++++- arch/powerpc/kvm/book3s_64_entry.S | 61 ++++++++++++---------------- 2 files changed, 45 insertions(+), 37 deletions(-) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index bf377bfeeb1a..f7fc6e078d4e 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1869,8 +1869,27 @@ EXC_VIRT_END(system_call, 0x4c00, 0x100) #ifdef CONFIG_KVM_BOOK3S_64_HANDLER TRAMP_REAL_BEGIN(kvm_hcall) + std r9,PACA_EXGEN+EX_R9(r13) + std r11,PACA_EXGEN+EX_R11(r13) + std r12,PACA_EXGEN+EX_R12(r13) + mfcr r9 mfctr r10 - SET_SCRATCH0(r10) /* Save r13 in SCRATCH0 */ + std r10,PACA_EXGEN+EX_R13(r13) + li r10,0 + std r10,PACA_EXGEN+EX_CFAR(r13) + std r10,PACA_EXGEN+EX_CTR(r13) + /* + * Save the PPR (on systems that support it) before changing to + * HMT_MEDIUM. That allows the KVM code to save that value into the + * guest state (it is the guest's PPR value). + */ +BEGIN_FTR_SECTION + mfspr r10,SPRN_PPR + std r10,PACA_EXGEN+EX_PPR(r13) +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) + + HMT_MEDIUM + #ifdef CONFIG_RELOCATABLE /* * Requires __LOAD_FAR_HANDLER beause kvmppc_hcall lives diff --git a/arch/powerpc/kvm/book3s_64_entry.S b/arch/powerpc/kvm/book3s_64_entry.S index 66170ea85bc2..a01046202eef 100644 --- a/arch/powerpc/kvm/book3s_64_entry.S +++ b/arch/powerpc/kvm/book3s_64_entry.S @@ -11,40 +11,30 @@ * These are branched to from interrupt handlers in exception-64s.S which set * IKVM_REAL or IKVM_VIRT, if HSTATE_IN_GUEST was found to be non-zero. */ + +/* + * This is a hcall, so register convention is as + * Documentation/powerpc/papr_hcalls.rst. + * + * This may also be a syscall from PR-KVM userspace that is to be + * reflected to the PR guest kernel, so registers may be set up for + * a system call rather than hcall. We don't currently clobber + * anything here, but the 0xc00 handler has already clobbered CTR + * and CR0, so PR-KVM can not support a guest kernel that preserves + * those registers across its system calls. + * + * The state of registers is as kvmppc_interrupt, except CFAR is not + * saved, R13 is not in SCRATCH0, and R10 does not contain the trap. + */ .global kvmppc_hcall .balign IFETCH_ALIGN_BYTES kvmppc_hcall: - /* - * This is a hcall, so register convention is as - * Documentation/powerpc/papr_hcalls.rst, with these additions: - * R13 = PACA - * guest R13 saved in SPRN_SCRATCH0 - * R10 = free - * guest r10 saved in PACA_EXGEN - * - * This may also be a syscall from PR-KVM userspace that is to be - * reflected to the PR guest kernel, so registers may be set up for - * a system call rather than hcall. We don't currently clobber - * anything here, but the 0xc00 handler has already clobbered CTR - * and CR0, so PR-KVM can not support a guest kernel that preserves - * those registers across its system calls. - */ - /* - * Save the PPR (on systems that support it) before changing to - * HMT_MEDIUM. That allows the KVM code to save that value into the - * guest state (it is the guest's PPR value). - */ -BEGIN_FTR_SECTION - mfspr r10,SPRN_PPR - std r10,HSTATE_PPR(r13) -END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) - HMT_MEDIUM - mfcr r10 - std r12,HSTATE_SCRATCH0(r13) - sldi r12,r10,32 - ori r12,r12,0xc00 - ld r10,PACA_EXGEN+EX_R10(r13) - b do_kvm_interrupt + ld r10,PACA_EXGEN+EX_R13(r13) + SET_SCRATCH0(r10) + li r10,0xc00 + /* Now we look like kvmppc_interrupt */ + li r11,PACA_EXGEN + b .Lgot_save_area /* * KVM interrupt entry occurs after GEN_INT_ENTRY runs, and follows that @@ -67,12 +57,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) kvmppc_interrupt: li r11,PACA_EXGEN cmpdi r10,0x200 - bgt+ 1f + bgt+ .Lgot_save_area li r11,PACA_EXMC - beq 1f + beq .Lgot_save_area li r11,PACA_EXNMI -1: add r11,r11,r13 - +.Lgot_save_area: + add r11,r11,r13 BEGIN_FTR_SECTION ld r12,EX_CFAR(r11) std r12,HSTATE_CFAR(r13) @@ -91,7 +81,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) ld r10,EX_R10(r11) ld r11,EX_R11(r11) -do_kvm_interrupt: /* * Hcalls and other interrupts come here after normalising register * contents and save locations: