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Wed, 29 Apr 2026 04:21:27 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 9749920B716C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1777461688; bh=ILqMNi8E0ZWRUMXGxnAYzHgDf8g8EDMKniRpfLKbTYs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jyfLNQ4dGfQxmjRYDIUE78qhAZTwkWKUr/vQMaG3cikg+1TjSrOeT1/Dmj8Jc7hTo BjwCghWEAi5MDbxgQdEthZepkfLxz7yr2KL6PpOaU4ZVm2Ov1XhH/1f3ZMV8vmlfbG WPMZ9T8GUtE3R/wX2coWqxm5dp3+BK7KjkcgsJv8= Date: Wed, 29 Apr 2026 13:21:24 +0200 From: Magnus Kulke To: Doru =?iso-8859-1?Q?Bl=E2nzeanu?= Cc: qemu-devel@nongnu.org, Wei Liu , Paolo Bonzini , Zhao Liu Subject: Re: [PATCH 4/6] target/i386/mshv: hv_vp_register_page setup for the vcpu Message-ID: References: <20260428135053.251200-1-dblanzeanu@linux.microsoft.com> <20260428135053.251200-5-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: <20260428135053.251200-5-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: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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, Apr 28, 2026 at 04:50:51PM +0300, Doru Blânzeanu wrote: > When the vcpu is created, call mmap to configure access to the register page. > > Update CPUArchState to store a pointer to the mmapped hv_vp_register_page. > > Signed-off-by: Doru Blânzeanu > --- > target/i386/cpu.h | 3 +++ > target/i386/mshv/mshv-cpu.c | 18 ++++++++++++++++++ > 2 files changed, 21 insertions(+) > > diff --git a/target/i386/cpu.h b/target/i386/cpu.h > index 0b539155c4..0108e2157b 100644 > --- a/target/i386/cpu.h > +++ b/target/i386/cpu.h > @@ -2016,6 +2016,9 @@ typedef struct CPUArchState { > uint64_t msr_bndcfgs; > uint64_t efer; > > + /* Shared register page */ > + struct hv_vp_register_page *regs_page; > + We probably want to put this behind a compile-time guard: #if defined(CONFIG_MSHV) ... #endif > /* 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..42b6fb1912 100644 > --- a/target/i386/mshv/mshv-cpu.c > +++ b/target/i386/mshv/mshv-cpu.c > @@ -1595,6 +1595,19 @@ void mshv_arch_init_vcpu(CPUState *cpu) > + sizeof(hv_input_get_vp_registers) > > HV_HYP_PAGE_SIZE)); > > + > + /* mmap the registers page */ > + void *rp = mmap(NULL, page, PROT_READ | PROT_WRITE, > + MAP_SHARED, mshv_vcpufd(cpu), > + MSHV_VP_MMAP_OFFSET_REGISTERS * page); nit: convention is to declare variables at the top of a fn: int cpu_fd = mshv_vcpufd(cpu); void *regs_page; ... regs_page = mmap(..., cpu_fd, ...); > + if (rp == MAP_FAILED) { > + warn_report("register page mmap failed, falling back to hypercalls: %s", We're not falling back at this specific place. so it probably makes sense to just say register page mmap failed and leave it at that here. > + strerror(errno)); > + env->regs_page = NULL; > + } else { > + env->regs_page = (struct hv_vp_register_page *) rp; > + } > + > state->hvcall_args.base = mem; > state->hvcall_args.input_page = mem; > state->hvcall_args.output_page = (uint8_t *)mem + page; > @@ -1608,6 +1621,11 @@ 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