{"id":2224392,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2224392/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260417105618.3621-32-magnuskulke@linux.microsoft.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.2/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260417105618.3621-32-magnuskulke@linux.microsoft.com>","list_archive_url":null,"date":"2026-04-17T10:56:15","name":"[31/34] target/i386/mshv: migrate XSAVE state","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"ff9c55a4539a33483486d35700c1420bea41d987","submitter":{"id":90753,"url":"http://patchwork.ozlabs.org/api/1.2/people/90753/?format=json","name":"Magnus Kulke","email":"magnuskulke@linux.microsoft.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260417105618.3621-32-magnuskulke@linux.microsoft.com/mbox/","series":[{"id":500310,"url":"http://patchwork.ozlabs.org/api/1.2/series/500310/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=500310","date":"2026-04-17T10:55:44","name":"Add migration support to the MSHV accelerator","version":1,"mbox":"http://patchwork.ozlabs.org/series/500310/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2224392/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2224392/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=linux.microsoft.com header.i=@linux.microsoft.com\n header.a=rsa-sha256 header.s=default header.b=UG7EHl7L;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists1p.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fxsLl3XWwz1yD3\n\tfor ; Fri, 17 Apr 2026 20:58:39 +1000 (AEST)","from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists1p.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from )\n\tid 1wDgu9-0005fY-TU; Fri, 17 Apr 2026 06:58:33 -0400","from eggs.gnu.org ([2001:470:142:3::10])\n by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from )\n id 1wDgu8-0005Rs-4B\n for qemu-devel@nongnu.org; Fri, 17 Apr 2026 06:58:32 -0400","from linux.microsoft.com ([13.77.154.182])\n by eggs.gnu.org with esmtp (Exim 4.90_1)\n (envelope-from ) id 1wDgu6-0001tc-1q\n for qemu-devel@nongnu.org; Fri, 17 Apr 2026 06:58:31 -0400","from DESKTOP-TUU1E5L.fritz.box (p5086d620.dip0.t-ipconnect.de\n [80.134.214.32])\n by linux.microsoft.com (Postfix) with ESMTPSA id EFA3E20B7001;\n Fri, 17 Apr 2026 03:58:15 -0700 (PDT)"],"DKIM-Filter":"OpenDKIM Filter v2.11.0 linux.microsoft.com EFA3E20B7001","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com;\n s=default; t=1776423498;\n bh=7gTom78x3K6oKCng+OiNrUvvmUvSvvHVMp0/uAOVRMk=;\n h=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n b=UG7EHl7L2JY25yroZFasVEt+gzalDMZViyWRdOXwO1behKsqN0XyOVSSvYlQxdGPE\n WwFGURb5Ezjs61qyP34lljWsnhXbCjII/tr5gEh3o8g3Hu+MNsrxf47jpvggB10E9R\n h+0dgd+68bWHM3OlJAcxoeFc2rPPkhrLXiSvzLEg=","From":"Magnus Kulke ","To":"qemu-devel@nongnu.org","Cc":"kvm@vger.kernel.org, Magnus Kulke ,\n Wei Liu , \"Michael S. Tsirkin\" ,\n\t=?utf-8?q?C=C3=A9dric_Le_Goater?= ,\n Zhao Liu ,\n Richard Henderson ,\n Paolo Bonzini , Wei Liu ,\n Magnus Kulke ,\n Alex Williamson ,\n Marcel Apfelbaum , =?utf-8?q?Philippe_Mathieu-D?=\n\t=?utf-8?q?aud=C3=A9?= ,\n Marcelo Tosatti ","Subject":"[PATCH 31/34] target/i386/mshv: migrate XSAVE state","Date":"Fri, 17 Apr 2026 12:56:15 +0200","Message-Id":"<20260417105618.3621-32-magnuskulke@linux.microsoft.com>","X-Mailer":"git-send-email 2.34.1","In-Reply-To":"<20260417105618.3621-1-magnuskulke@linux.microsoft.com>","References":"<20260417105618.3621-1-magnuskulke@linux.microsoft.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Received-SPF":"pass client-ip=13.77.154.182;\n envelope-from=magnuskulke@linux.microsoft.com; helo=linux.microsoft.com","X-Spam_score_int":"-42","X-Spam_score":"-4.3","X-Spam_bar":"----","X-Spam_report":"(-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001,\n SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"We implement fn's that roundtrip XSAVE state in migration. We are using\nthe xsave_helper routines to move individual components from CPUX86State\nto an xsave_buf and then we have to compact the buffer to XSAVEC format,\nwhich is what the hypervisor expects.\n\nAnd the same applies in the other direction for restoring state from the\nhypervisor.\n\nSigned-off-by: Magnus Kulke \n---\n target/i386/cpu.h | 2 +-\n target/i386/mshv/mshv-cpu.c | 100 +++++++++++++++++++++++++++++++++++-\n 2 files changed, 100 insertions(+), 2 deletions(-)","diff":"diff --git a/target/i386/cpu.h b/target/i386/cpu.h\nindex cd5d5a5369..0f30f0dd5b 100644\n--- a/target/i386/cpu.h\n+++ b/target/i386/cpu.h\n@@ -2272,7 +2272,7 @@ typedef struct CPUArchState {\n int64_t user_tsc_khz; /* for sanity check only */\n uint64_t apic_bus_freq;\n uint64_t tsc;\n-#if defined(CONFIG_KVM) || defined(CONFIG_HVF)\n+#if defined(CONFIG_KVM) || defined(CONFIG_HVF) || defined(CONFIG_MSHV)\n void *xsave_buf;\n uint32_t xsave_buf_len;\n #endif\ndiff --git a/target/i386/mshv/mshv-cpu.c b/target/i386/mshv/mshv-cpu.c\nindex 517b38a32d..5b0b8bda16 100644\n--- a/target/i386/mshv/mshv-cpu.c\n+++ b/target/i386/mshv/mshv-cpu.c\n@@ -109,6 +109,78 @@ static enum hv_register_name FPU_REGISTER_NAMES[26] = {\n \n static int set_special_regs(const CPUState *cpu);\n \n+static int get_xsave_state(CPUState *cpu)\n+{\n+ X86CPU *x86cpu = X86_CPU(cpu);\n+ CPUX86State *env = &x86cpu->env;\n+ int cpu_fd = mshv_vcpufd(cpu);\n+ int ret;\n+ void *xsavec_buf;\n+ const size_t page = HV_HYP_PAGE_SIZE;\n+ size_t xsavec_buf_len = page;\n+\n+ /* TODO: should properly determine xsavec size based on CPUID */\n+ xsavec_buf = qemu_memalign(page, xsavec_buf_len);\n+ memset(xsavec_buf, 0, xsavec_buf_len);\n+\n+ struct mshv_get_set_vp_state args = {\n+ .type = MSHV_VP_STATE_XSAVE,\n+ .buf_sz = xsavec_buf_len,\n+ .buf_ptr = (uintptr_t)xsavec_buf,\n+ };\n+\n+ ret = ioctl(cpu_fd, MSHV_GET_VP_STATE, &args);\n+ if (ret < 0) {\n+ error_report(\"failed to get xsave state: %s\", strerror(errno));\n+ return -errno;\n+ }\n+\n+ ret = decompact_xsave_area(xsavec_buf, xsavec_buf_len, env);\n+ g_free(xsavec_buf);\n+ if (ret < 0) {\n+ error_report(\"failed to decompact xsave area\");\n+ return ret;\n+ }\n+ x86_cpu_xrstor_all_areas(x86cpu, env->xsave_buf, env->xsave_buf_len);\n+\n+ return 0;\n+}\n+\n+static int set_xsave_state(const CPUState *cpu)\n+{\n+ X86CPU *x86cpu = X86_CPU(cpu);\n+ CPUX86State *env = &x86cpu->env;\n+ int cpu_fd = mshv_vcpufd(cpu);\n+ int ret;\n+ void *xsavec_buf;\n+ size_t page = HV_HYP_PAGE_SIZE, xsavec_buf_len;\n+\n+ /* allocate and populate compacted buffer */\n+ xsavec_buf = qemu_memalign(page, page);\n+ xsavec_buf_len = page;\n+\n+ /* save registers to standard format buffer */\n+ x86_cpu_xsave_all_areas(x86cpu, env->xsave_buf, env->xsave_buf_len);\n+\n+ /* store compacted version of xsave area in xsavec_buf */\n+ compact_xsave_area(env, xsavec_buf, xsavec_buf_len);\n+\n+ struct mshv_get_set_vp_state args = {\n+ .type = MSHV_VP_STATE_XSAVE,\n+ .buf_sz = xsavec_buf_len,\n+ .buf_ptr = (uintptr_t)xsavec_buf,\n+ };\n+\n+ ret = ioctl(cpu_fd, MSHV_SET_VP_STATE, &args);\n+ g_free(xsavec_buf);\n+ if (ret < 0) {\n+ error_report(\"failed to set xsave state: %s\", strerror(errno));\n+ return -errno;\n+ }\n+\n+ return 0;\n+}\n+\n static int get_lapic(CPUState *cpu)\n {\n X86CPU *x86cpu = X86_CPU(cpu);\n@@ -766,6 +838,11 @@ int mshv_arch_load_vcpu_state(CPUState *cpu)\n return ret;\n }\n \n+ ret = get_xsave_state(cpu);\n+ if (ret < 0) {\n+ return ret;\n+ }\n+\n ret = get_lapic(cpu);\n if (ret < 0) {\n return ret;\n@@ -1258,6 +1335,11 @@ int mshv_arch_store_vcpu_state(const CPUState *cpu)\n return ret;\n }\n \n+ ret = set_xsave_state(cpu);\n+ if (ret < 0) {\n+ return ret;\n+ }\n+\n /* INVARIANT: special regs (APIC_BASE) must be restored before LAPIC */\n ret = set_lapic(cpu);\n if (ret < 0) {\n@@ -1786,9 +1868,10 @@ void mshv_arch_init_vcpu(CPUState *cpu)\n X86CPU *x86_cpu = X86_CPU(cpu);\n CPUX86State *env = &x86_cpu->env;\n AccelCPUState *state = cpu->accel;\n- size_t page = HV_HYP_PAGE_SIZE;\n+ size_t page = HV_HYP_PAGE_SIZE, xsave_len;\n void *mem = qemu_memalign(page, 2 * page);\n int ret;\n+ X86XSaveHeader *header;\n \n /* sanity check, to make sure we don't overflow the page */\n QEMU_BUILD_BUG_ON((MAX_REGISTER_COUNT\n@@ -1802,6 +1885,17 @@ void mshv_arch_init_vcpu(CPUState *cpu)\n \n env->emu_mmio_buf = g_new(char, 4096);\n \n+ /* Initialize XSAVE buffer page-aligned */\n+ /* TODO: pick proper size based on CPUID */\n+ xsave_len = page;\n+ env->xsave_buf = qemu_memalign(page, xsave_len);\n+ env->xsave_buf_len = xsave_len;\n+ memset(env->xsave_buf, 0, env->xsave_buf_len);\n+\n+ /* we need to set the compacted format bit in xsave header for mshv */\n+ header = (X86XSaveHeader *)(env->xsave_buf + sizeof(X86LegacyXSaveArea));\n+ header->xcomp_bv = header->xstate_bv | (1ULL << 63);\n+\n /*\n * TODO: populate topology info:\n * X86CPUTopoInfo *topo_info = &env->topo_info;\n@@ -1826,6 +1920,10 @@ void mshv_arch_destroy_vcpu(CPUState *cpu)\n g_free(state->hvcall_args.base);\n state->hvcall_args = (MshvHvCallArgs){0};\n g_clear_pointer(&env->emu_mmio_buf, g_free);\n+\n+ qemu_vfree(env->xsave_buf);\n+ env->xsave_buf = NULL;\n+ env->xsave_buf_len = 0;\n }\n \n /*\n","prefixes":["31/34"]}