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Wed, 6 May 2026 07:36:13 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 0295120B7165 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1778078175; bh=FKUfSDsIXOoZFWgGKOL6KFKf7v4gDq85YHXef0xMwsw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=M7SI55G/WcRHfMYvgmBXam9yrGusXPCojVPY6LZwGshuEmLlhfJo5V8HOqpRA0GcU 3c2AQnyAkQ71cjDwVlk9EAG/OU0qMFew5Htvc8TkoeRjRENMGmz7KzFaJknsN+npS9 SlOACibC0/dffJNGsFSVkp+2nme8jCTfAKUjx1p0= Date: Wed, 6 May 2026 16:36:13 +0200 From: Magnus Kulke To: Doru =?iso-8859-1?Q?Bl=E2nzeanu?= Cc: qemu-devel@nongnu.org, Zhao Liu , Wei Liu , Paolo Bonzini Subject: Re: [PATCH v2 4/7] target/i386/mshv: hv_vp_register_page setup for the vcpu Message-ID: References: <20260505185028.237207-1-dblanzeanu@linux.microsoft.com> <20260505185028.237207-5-dblanzeanu@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260505185028.237207-5-dblanzeanu@linux.microsoft.com> Received-SPF: pass client-ip=13.77.154.182; envelope-from=magnuskulke@linux.microsoft.com; helo=linux.microsoft.com X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, May 05, 2026 at 09:50:25PM +0300, Doru Blânzeanu wrote: > When the vcpu is created, call mmap to configure access to the register page. > In case the call to mmap fails, we log an error and continue with the > previous logic (using hypercalls). > > Update CPUArchState to store a pointer to the mmapped hv_vp_register_page. > > Signed-off-by: Doru Blânzeanu > --- > target/i386/cpu.h | 5 +++++ > target/i386/mshv/mshv-cpu.c | 22 ++++++++++++++++++++++ > 2 files changed, 27 insertions(+) > > diff --git a/target/i386/cpu.h b/target/i386/cpu.h > index 16de67e546..fd4c3712b1 100644 > --- a/target/i386/cpu.h > +++ b/target/i386/cpu.h > @@ -2019,6 +2019,11 @@ typedef struct CPUArchState { > uint64_t msr_bndcfgs; > uint64_t efer; > > +#ifdef CONFIG_MSHV > + /* Shared register page */ > + struct hv_vp_register_page *regs_page; > +#endif since this is declared before this marker /* Fields up to this point are cleared by a CPU reset */ struct {} end_reset_fields; the pointer will be zeroed out on init, best move it after the emu_mmio_buf field. > + > /* Beginning of state preserved by INIT (dummy marker). */ > struct {} start_init_save; > > diff --git a/target/i386/mshv/mshv-cpu.c b/target/i386/mshv/mshv-cpu.c > index 9defd05db6..3a3c269c33 100644 > --- a/target/i386/mshv/mshv-cpu.c > +++ b/target/i386/mshv/mshv-cpu.c > @@ -1587,6 +1587,7 @@ void mshv_arch_init_vcpu(CPUState *cpu) > CPUX86State *env = &x86_cpu->env; > AccelCPUState *state = cpu->accel; > size_t page = HV_HYP_PAGE_SIZE; > + void *regs_page; > void *mem = qemu_memalign(page, 2 * page); > > /* sanity check, to make sure we don't overflow the page */ > @@ -1595,6 +1596,22 @@ void mshv_arch_init_vcpu(CPUState *cpu) > + sizeof(hv_input_get_vp_registers) > > HV_HYP_PAGE_SIZE)); > > + > + /* mmap the registers page */ > + regs_page = mmap(NULL, page, PROT_READ | PROT_WRITE, > + MAP_SHARED, mshv_vcpufd(cpu), > + MSHV_VP_MMAP_OFFSET_REGISTERS * page); > + if (regs_page == MAP_FAILED) { > + /* > + * Error is not fatal, but we won't be able to use the > + * fast path for register access > + */ > + error_report("register page mmap failed: %s", strerror(errno)); > + env->regs_page = NULL; > + } else { > + env->regs_page = (struct hv_vp_register_page *) regs_page; > + } > + > state->hvcall_args.base = mem; > state->hvcall_args.input_page = mem; > state->hvcall_args.output_page = (uint8_t *)mem + page; > @@ -1608,6 +1625,11 @@ void mshv_arch_destroy_vcpu(CPUState *cpu) > CPUX86State *env = &x86_cpu->env; > AccelCPUState *state = cpu->accel; > > + /* Unmap the register page */ > + if (env->regs_page) { > + munmap(env->regs_page, HV_HYP_PAGE_SIZE); > + env->regs_page = NULL; > + } > g_free(state->hvcall_args.base); > state->hvcall_args = (MshvHvCallArgs){0}; > g_clear_pointer(&env->emu_mmio_buf, g_free); > -- > 2.53.0