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AFNElJ+xgobLDw4K1s224w86BpuA8Y0JmsBNRcUU1VCV/v65Fj9V9aO5D3kb7pOXxFzOM5wGlKh3hl+YBUhX/KA=@vger.kernel.org X-Gm-Message-State: AOJu0Yzyl9aP8AevgvSkiEUhtgtlmt0Pj642jC1p+FDdJgD0WKmfqMaj 0gKvcs5rExwN0zlnkkfFM0XpvQjWYSh3+jhc7qoXclEa4prPmu6AVhnO9woD41M7xJdSn/f0qmk nQlIQrMIaFgzOoG/4wCA2XWywUg== X-Received: from pfoo12.prod.google.com ([2002:a05:6a00:1a0c:b0:82f:bc93:4ae2]) (user=ackerleytng job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:1993:b0:82f:120:fd6f with SMTP id d2e1a72fcca58-834dd919817mr4905304b3a.0.1777419212551; Tue, 28 Apr 2026 16:33:32 -0700 (PDT) Date: Tue, 28 Apr 2026 16:33:23 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@google.com> X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog Message-ID: <8c0dc96e0776bdcffc4d2e1a9d7336f106289a48.1777418884.git.ackerleytng@google.com> Subject: [POC PATCH 3/6] KVM: selftests: Make guest_code_xsave more friendly From: Ackerley Tng To: devnull+ackerleytng.google.com@kernel.org Cc: ackerleytng@google.com, aik@amd.com, akpm@linux-foundation.org, andrew.jones@linux.dev, aneesh.kumar@kernel.org, axelrasmussen@google.com, baohua@kernel.org, bhe@redhat.com, binbin.wu@linux.intel.com, bp@alien8.de, brauner@kernel.org, chao.p.peng@linux.intel.com, chrisl@kernel.org, corbet@lwn.net, dave.hansen@linux.intel.com, david@kernel.org, forkloop@google.com, hpa@zytor.com, ira.weiny@intel.com, jgg@ziepe.ca, jmattson@google.com, jthoughton@google.com, kas@kernel.org, kasong@tencent.com, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, michael.roth@amd.com, mingo@redhat.com, nphamcs@gmail.com, oupton@kernel.org, pankaj.gupta@amd.com, pbonzini@redhat.com, pratyush@kernel.org, qi.zheng@linux.dev, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, rostedt@goodmis.org, seanjc@google.com, shakeel.butt@linux.dev, shikemeng@huaweicloud.com, shivankg@amd.com, shuah@kernel.org, skhan@linuxfoundation.org, steven.price@arm.com, suzuki.poulose@arm.com, tabba@google.com, tglx@kernel.org, vannapurve@google.com, vbabka@kernel.org, weixugc@google.com, willy@infradead.org, wyihan@google.com, x86@kernel.org, yan.y.zhao@intel.com, youngjun.park@lge.com, yuanchu@google.com Content-Type: text/plain; charset="UTF-8" The original implementation of guest_code_xsave makes a jmp to guest_sev_es_code in inline assembly. When code that uses guest_sev_es_code is removed, guest_sev_es_code will be optimized out, leading to a linking error since guest_code_xsave still tries to jmp to guest_sev_es_code. Rewrite guest_code_xsave() to instead make a call, in C, to guest_sev_es_code(), so that usage of guest_sev_es_code() is made known to the compiler. This rewriting also gives a name to the xsave inline assembly, improving readability. Signed-off-by: Ackerley Tng --- .../selftests/kvm/x86/sev_smoke_test.c | 24 +++++++++++++------ 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/kvm/x86/sev_smoke_test.c b/tools/testing/selftests/kvm/x86/sev_smoke_test.c index 1a49ee3915864..8b859adf4cf6f 100644 --- a/tools/testing/selftests/kvm/x86/sev_smoke_test.c +++ b/tools/testing/selftests/kvm/x86/sev_smoke_test.c @@ -80,13 +80,23 @@ static void guest_sev_code(void) GUEST_DONE(); } -/* Stash state passed via VMSA before any compiled code runs. */ -extern void guest_code_xsave(void); -asm("guest_code_xsave:\n" - "mov $" __stringify(XFEATURE_MASK_X87_AVX) ", %eax\n" - "xor %edx, %edx\n" - "xsave (%rdi)\n" - "jmp guest_sev_es_code"); +static void xsave_all_registers(void *addr) +{ + __asm__ __volatile__( + "mov $" __stringify(XFEATURE_MASK_X87_AVX) ", %eax\n" + "xor %edx, %edx\n" + "xsave (%0)" + : + : "r"(addr) + : "eax", "edx", "memory" + ); +} + +static void guest_code_xsave(void *vmsa_gva) +{ + xsave_all_registers(vmsa_gva); + guest_sev_es_code(); +} static void compare_xsave(u8 *from_host, u8 *from_guest) { -- 2.54.0.545.g6539524ca2-goog