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Tsirkin" , Peter Maydell , Zhao Liu Subject: [PATCH v2 22/38] whpx: i386: add HV_X64_MSR_GUEST_IDLE when !kernel-irqchip Date: Mon, 20 Apr 2026 12:42:32 +0200 Message-ID: <20260420104248.86702-23-mohamed@unpredictable.fr> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260420104248.86702-1-mohamed@unpredictable.fr> References: <20260420104248.86702-1-mohamed@unpredictable.fr> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-GUID: dE6Sy28pQ6v8HPLMu6rOC2g_RSQ33-4c X-Authority-Info-Out: v=2.4 cv=DOGCIiNb c=1 sm=1 tr=0 ts=69e60365 cx=c_apl:c_pps:t_out a=qkKslKyYc0ctBTeLUVfTFg==:117 a=A5OVakUREuEA:10 a=VkNPw1HP01LnGYTKEx00:22 a=mSEN7FZ2dYRJNo9PPvgA:9 X-Proofpoint-ORIG-GUID: dE6Sy28pQ6v8HPLMu6rOC2g_RSQ33-4c X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNDIwMDEwNCBTYWx0ZWRfX/7s1U1iEpY8u ZJ2HMCKQaIoxG9HSWTjkfi5jX7O3mzViV6jBElXOxoBTyurbtq+LN/WgjirDgGQxJkIzTSB1U2J Rb6XaLeljwlP5V8WSRjrGAwBa25rbFzhBAksOW7VOAJITE5H9ZFHWYTDZeylu05nsV+nIGrqKMQ xIOqI6mTbBzxTWejXf+cIZnoZfxQEodb4HJXWu+KG1ktiD7Xk7BpyN3p7Cci8fKv0cdtr1/U/rF NJrRChgr61UTrYYIZLYaKxrIFs/oYmSLlnOL/nCTE06LAzVRVhr5KI7dHkdTY8dEv9Xn9DYk8xh xe4PHvaTz6HNxO/IyYImGhROQotso7+Brh2uHL69Fze17sQxglxo7IIlJibkkY= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-04-20_02,2026-04-17_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 lowpriorityscore=0 mlxscore=0 spamscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 mlxlogscore=999 clxscore=1030 classifier=spam authscore=0 adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2604200104 Received-SPF: pass client-ip=57.103.75.103; envelope-from=mohamed@unpredictable.fr; helo=outbound.ms.icloud.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-arm@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-arm-bounces+qemu-arm=archiver.kernel.org@nongnu.org Sender: qemu-arm-bounces+qemu-arm=archiver.kernel.org@nongnu.org Add support for an oddball HV_X64_MSR_GUEST_IDLE not-quite-an-HLT that wakes the vCPU even if EFLAGS.IF is set. Signed-off-by: Mohamed Mediouni --- target/i386/whpx/whpx-all.c | 46 ++++++++++++++++++++++++++++++++++--- 1 file changed, 43 insertions(+), 3 deletions(-) diff --git a/target/i386/whpx/whpx-all.c b/target/i386/whpx/whpx-all.c index 3af5f936d4..4dc4030d87 100644 --- a/target/i386/whpx/whpx-all.c +++ b/target/i386/whpx/whpx-all.c @@ -52,6 +52,7 @@ /* for kernel-irqchip=off */ #define HV_X64_MSR_APIC_FREQUENCY 0x40000023 #define HV_X64_MSR_VP_ASSIST_PAGE 0x40000073 +#define HV_X64_MSR_GUEST_IDLE 0x400000f0 static bool is_modern_os = true; @@ -1543,13 +1544,16 @@ static vaddr whpx_vcpu_get_pc(CPUState *cpu, bool exit_context_valid) } } -static int whpx_handle_halt(CPUState *cpu) +static int whpx_handle_halt_generic(CPUState *cpu) { + X86CPU *x86_cpu = X86_CPU(cpu); + CPUX86State *env = &x86_cpu->env; + int ret = 0; bql_lock(); if (!(cpu_test_interrupt(cpu, CPU_INTERRUPT_HARD) && - (cpu_env(cpu)->eflags & IF_MASK)) && + ((cpu_env(cpu)->eflags & IF_MASK) || env->hflags2 & HF2_HYPERV_HLT_MASK)) && !cpu_test_interrupt(cpu, CPU_INTERRUPT_NMI)) { cpu->exception_index = EXCP_HLT; cpu->halted = true; @@ -1560,6 +1564,27 @@ static int whpx_handle_halt(CPUState *cpu) return ret; } +static int whpx_handle_halt(CPUState *cpu) +{ + int ret = 0; + + ret = whpx_handle_halt_generic(cpu); + + return ret; +} + +static int whpx_handle_hyperv_guestidle(CPUState *cpu) +{ + X86CPU *x86_cpu = X86_CPU(cpu); + CPUX86State *env = &x86_cpu->env; + int ret = 0; + + env->hflags2 |= HF2_HYPERV_HLT_MASK; + ret = whpx_handle_halt_generic(cpu); + + return ret; +} + static void whpx_vcpu_kick_out_of_hlt(CPUState *cpu) { WHV_REGISTER_VALUE reg; @@ -1763,9 +1788,10 @@ static void whpx_vcpu_process_async_events(CPUState *cpu) } if ((cpu_test_interrupt(cpu, CPU_INTERRUPT_HARD) && - (env->eflags & IF_MASK)) || + ((env->eflags & IF_MASK) || env->hflags2 & HF2_HYPERV_HLT_MASK)) || cpu_test_interrupt(cpu, CPU_INTERRUPT_NMI)) { cpu->halted = false; + env->hflags2 &= ~HF2_HYPERV_HLT_MASK; } if (cpu_test_interrupt(cpu, CPU_INTERRUPT_SIPI)) { @@ -2035,6 +2061,20 @@ int whpx_vcpu_run(CPUState *cpu) } } + /* + * Windows and Linux both use this MSR. + * Windows 11 25H2 uses it even when not advertised. + */ + if (vcpu->exit_ctx.MsrAccess.MsrNumber == HV_X64_MSR_GUEST_IDLE + && !vcpu->exit_ctx.MsrAccess.AccessInfo.IsWrite + && !whpx_irqchip_in_kernel() + && whpx->hyperv_enlightenments_enabled) { + is_known_msr = 1; + whpx_bump_rip(cpu, &vcpu->exit_ctx); + ret = whpx_handle_hyperv_guestidle(cpu); + break; + } + /* * Linux tries to use it anyway even when not exposed. * Ignore the write as the VP assist page is not used. -- 2.50.1 (Apple Git-155)