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[37.24.206.209]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a868f29a4e0sm633318666b.58.2024.08.26.01.21.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 26 Aug 2024 01:21:21 -0700 (PDT) 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 Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 2d47ce4f-6384-11ef-8776-851b0ebba9a2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1724660481; x=1725265281; darn=lists.xenproject.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=JxSRI57/dbar7REbw2c2FcaNkJ+kScc0xmfODQhklvo=; b=ahLmoe3lVtl+005nmwbKIAumXdFFi9FfeaLN9X4gbgW+fwa1ipfP2oDyRYLlBKYVvD vmHtumXOLGieHkGc6gxcvdpGfsjgWnkIY9aCjob2b+t9wZ2KnALSzXb/PVftMhSDBGYc kZTkKUtY7t5OVUXb/wivOY8dx0W0HsigadOvdR0dgEM1OMkuYO3E0bk/R5N0vZvicNd3 kKArwVqdVIy6ruVYVJeinb//KRSHD7BXBeiHLFq/T97SlIBTn64rV4EjLcZ1eZ+IO0WD PG6Fwg4StDXfg/TpVH0X/M3048TuSs1cWE4fUxkBKRsV4FD4kNV8dgha06vK1xyeLgEo Oq/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724660481; x=1725265281; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=JxSRI57/dbar7REbw2c2FcaNkJ+kScc0xmfODQhklvo=; b=Rjyn2HNaf3ro/jhESw1KrupEAdYQjaEhaEJSFnrNWmJV0CD4w9qOnXS05pbukJTERX ONORLHzd1QIMMBVwF8f0aAEa2gBIWXbzOJzRopy4FyHiTJz2UAsFqsQyqqPv/R83wwFo rMAvAT+J3W1D9R/RgrDx/2+n5bZDG8okztp2Gmi8AkMuiS/5BGy585EYqImSWss3Bk/v KmBpB/2n5Dz75HtsaodbGfYKvlywVUB56qhgCbMONY9yePORa/anllAy4BH6RgdGkivq 2cHJISh+9rG0CE0fNKC6wV02DOdaaQyj0jhptAuKAetzlC4RconW/1/oi9TpTaBbUyMx 4hpw== X-Forwarded-Encrypted: i=1; AJvYcCUqVSx3J2Mh6/BpD+rHamLn4zSU+jB4rEpAo3MOpDlq1RWZU9naBm60EXy5fMqmFs0DI9HeAXzSKGw=@lists.xenproject.org X-Gm-Message-State: AOJu0YyxzAz8/Xxj/M2TUaBRkf6FeaajLsMPJ+Sl3NEpkYIm4OA4eemc 7Z7RwI5Gp2L3HAMDX2SO1EmKDg+WCpT4izi+tpjm2533m1b26HoUcuV60ZTBhg== X-Google-Smtp-Source: AGHT+IHVnv/pN3wjA1meTxPQ4YcECe/NmOQ16cCDdbt1spC4VxzQL60QkHhEkwVtvOYYFGT6x15dew== X-Received: by 2002:a17:906:f59e:b0:a7a:9144:e23b with SMTP id a640c23a62f3a-a86a52b6124mr528268766b.19.1724660481335; Mon, 26 Aug 2024 01:21:21 -0700 (PDT) Message-ID: <55e6dc6c-344a-4483-90c2-e414ef4bc869@suse.com> Date: Mon, 26 Aug 2024 10:21:22 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] Avoid additional relocations in trampoline code To: Frediano Ziglio Cc: Andrew Cooper , =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= , Alejandro Vallejo , xen-devel@lists.xenproject.org References: <20240822152953.489136-1-frediano.ziglio@cloud.com> Content-Language: en-US From: Jan Beulich Autocrypt: addr=jbeulich@suse.com; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL In-Reply-To: <20240822152953.489136-1-frediano.ziglio@cloud.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 22.08.2024 17:29, Frediano Ziglio wrote: > The trampoline could have "manual" relocation entries (created > by assembly macros and some code to use them) and (in case of PE) > normal executable relocations. > Remove all normal executable ones. In this way we don't have to > worry about applying both correctly (they need proper order > which is hard to spot looking at the code). > > Signed-off-by: Frediano Ziglio I think this wants splitting into one patch replacing sym_offs() and a 2nd one introducing the hand-crafted __XEN_VIRT_START additions (which may want macro-izing). Plus the justification for the change wants extending, to actually explain what the problem is - after all there's no issue anywhere right now. > --- a/xen/arch/x86/boot/trampoline.S > +++ b/xen/arch/x86/boot/trampoline.S > @@ -73,7 +73,7 @@ trampoline_protmode_entry: > mov %ecx,%cr4 > > /* Load pagetable base register. */ > - mov $sym_offs(idle_pg_table),%eax > + mov $idle_pg_table_pa, %eax > add bootsym_rel(trampoline_xen_phys_start,4,%eax) > mov %eax,%cr3 > > @@ -113,7 +113,7 @@ trampoline_protmode_entry: > .code64 > start64: > /* Jump to high mappings. */ > - movabs $__high_start, %rdi > + movabs $__high_start_pa + __XEN_VIRT_START, %rdi > jmpq *%rdi > > #include "video.h" > --- a/xen/arch/x86/boot/wakeup.S > +++ b/xen/arch/x86/boot/wakeup.S > @@ -99,7 +99,7 @@ wakeup_32: > mov $bootsym_rel(wakeup_stack, 4, %esp) > > # check saved magic again > - mov $sym_offs(saved_magic),%eax > + mov $saved_magic_pa, %eax > add bootsym_rel(trampoline_xen_phys_start, 4, %eax) > mov (%eax), %eax > cmp $0x9abcdef0, %eax > @@ -112,7 +112,7 @@ wakeup_32: > mov %ecx, %cr4 > > /* Load pagetable base register */ > - mov $sym_offs(idle_pg_table),%eax > + mov $idle_pg_table_pa ,%eax > add bootsym_rel(trampoline_xen_phys_start,4,%eax) > mov %eax,%cr3 > > @@ -156,7 +156,7 @@ wakeup_32: > .code64 > wakeup_64: > /* Jump to high mappings and the higher-level wakeup code. */ > - movabs $s3_resume, %rbx > + movabs $s3_resume_pa + __XEN_VIRT_START, %rbx > jmp *%rbx > > bogus_saved_magic: With the sym_offs() uses gone, I think it would be best if the macro was #undef-ed ahead of the inclusion of trampoline.S. Since x86_64.S uses the macro, that'll require careful re-arrangement of #include order. > --- a/xen/arch/x86/xen.lds.S > +++ b/xen/arch/x86/xen.lds.S > @@ -71,7 +71,12 @@ SECTIONS > __2M_text_start = .; /* Start of 2M superpages, mapped RX. */ > #endif > > - start_pa = ABSOLUTE(start - __XEN_VIRT_START); > +#define DEFINE_PA_ADDRESS(sym) sym ## _pa = ABSOLUTE(sym - __XEN_VIRT_START) > + DEFINE_PA_ADDRESS(start); > + DEFINE_PA_ADDRESS(saved_magic); > + DEFINE_PA_ADDRESS(idle_pg_table); > + DEFINE_PA_ADDRESS(__high_start); > + DEFINE_PA_ADDRESS(s3_resume); > > . = __XEN_VIRT_START + XEN_IMG_OFFSET; > _start = .; For the cases where in assembly code you add __XEN_VIRT_START this is pretty odd: You subtract the value here just to add it back there. Did you consider a more straightforward approach, like introducing absolute xxx_va symbols? Also, as a general request: Can you please become used to adding meaningful subject prefixes to your patches? Jan