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envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, DKIM_INVALID=0.1, DKIM_SIGNED=0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@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-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Magnus Kulke There are hvcalls that are invoked during MMIO exits, the payload is of dynamic size. To avoid heap allocations we can use preallocated pages as in/out buffer for those calls. A page is reserved per vCPU and used for set/get register hv calls. Signed-off-by: Magnus Kulke Link: https://lore.kernel.org/r/20250916164847.77883-26-magnuskulke@linux.microsoft.com [Use standard MAX_CONST macro; mshv.h/mshv_int.h split. - Paolo] Signed-off-by: Paolo Bonzini --- include/system/mshv_int.h | 7 +++++++ accel/mshv/mshv-all.c | 2 +- target/i386/mshv/mshv-cpu.c | 38 +++++++++++++++++++++++++------------ 3 files changed, 34 insertions(+), 13 deletions(-) diff --git a/include/system/mshv_int.h b/include/system/mshv_int.h index 6350c69e9d3..490563c1ab2 100644 --- a/include/system/mshv_int.h +++ b/include/system/mshv_int.h @@ -20,9 +20,16 @@ typedef struct hyperv_message hv_message; +typedef struct MshvHvCallArgs { + void *base; + void *input_page; + void *output_page; +} MshvHvCallArgs; + struct AccelCPUState { int cpufd; bool dirty; + MshvHvCallArgs hvcall_args; }; typedef struct MshvMemoryListener { diff --git a/accel/mshv/mshv-all.c b/accel/mshv/mshv-all.c index 5edfcbad9d2..45174f7c4eb 100644 --- a/accel/mshv/mshv-all.c +++ b/accel/mshv/mshv-all.c @@ -399,8 +399,8 @@ static int mshv_init_vcpu(CPUState *cpu) uint8_t vp_index = cpu->cpu_index; int ret; - mshv_arch_init_vcpu(cpu); cpu->accel = g_new0(AccelCPUState, 1); + mshv_arch_init_vcpu(cpu); ret = mshv_create_vcpu(vm_fd, vp_index, &cpu->accel->cpufd); if (ret < 0) { diff --git a/target/i386/mshv/mshv-cpu.c b/target/i386/mshv/mshv-cpu.c index de87142bffc..1f7b9cb37ec 100644 --- a/target/i386/mshv/mshv-cpu.c +++ b/target/i386/mshv/mshv-cpu.c @@ -34,6 +34,10 @@ #include +#define MAX_REGISTER_COUNT (MAX_CONST(ARRAY_SIZE(STANDARD_REGISTER_NAMES), \ + MAX_CONST(ARRAY_SIZE(SPECIAL_REGISTER_NAMES), \ + ARRAY_SIZE(FPU_REGISTER_NAMES)))) + static enum hv_register_name STANDARD_REGISTER_NAMES[18] = { HV_X64_REGISTER_RAX, HV_X64_REGISTER_RBX, @@ -151,7 +155,7 @@ int mshv_set_generic_regs(const CPUState *cpu, const hv_register_assoc *assocs, int cpu_fd = mshv_vcpufd(cpu); int vp_index = cpu->cpu_index; size_t in_sz, assocs_sz; - hv_input_set_vp_registers *in; + hv_input_set_vp_registers *in = cpu->accel->hvcall_args.input_page; struct mshv_root_hvcall args = {0}; int ret; @@ -160,7 +164,7 @@ int mshv_set_generic_regs(const CPUState *cpu, const hv_register_assoc *assocs, in_sz = sizeof(hv_input_set_vp_registers) + assocs_sz; /* fill the input struct */ - in = g_malloc0(in_sz); + memset(in, 0, sizeof(hv_input_set_vp_registers)); in->vp_index = vp_index; memcpy(in->elements, assocs, assocs_sz); @@ -172,7 +176,6 @@ int mshv_set_generic_regs(const CPUState *cpu, const hv_register_assoc *assocs, /* perform the call */ ret = mshv_hvcall(cpu_fd, &args); - g_free(in); if (ret < 0) { error_report("Failed to set registers"); return -1; @@ -193,8 +196,8 @@ static int get_generic_regs(CPUState *cpu, hv_register_assoc *assocs, { int cpu_fd = mshv_vcpufd(cpu); int vp_index = cpu->cpu_index; - hv_input_get_vp_registers *in; - hv_register_value *values; + hv_input_get_vp_registers *in = cpu->accel->hvcall_args.input_page; + hv_register_value *values = cpu->accel->hvcall_args.output_page; size_t in_sz, names_sz, values_sz; int i, ret; struct mshv_root_hvcall args = {0}; @@ -204,15 +207,14 @@ static int get_generic_regs(CPUState *cpu, hv_register_assoc *assocs, in_sz = sizeof(hv_input_get_vp_registers) + names_sz; /* fill the input struct */ - in = g_malloc0(in_sz); + memset(in, 0, sizeof(hv_input_get_vp_registers)); in->vp_index = vp_index; for (i = 0; i < n_regs; i++) { in->names[i] = assocs[i].name; } - /* allocate value output buffer */ + /* determine size of value output buffer */ values_sz = n_regs * sizeof(union hv_register_value); - values = g_malloc0(values_sz); /* create the hvcall envelope */ args.code = HVCALL_GET_VP_REGISTERS; @@ -224,16 +226,13 @@ static int get_generic_regs(CPUState *cpu, hv_register_assoc *assocs, /* perform the call */ ret = mshv_hvcall(cpu_fd, &args); - g_free(in); if (ret < 0) { - g_free(values); error_report("Failed to retrieve registers"); return -1; } /* assert we got all registers */ if (args.reps != n_regs) { - g_free(values); error_report("Failed to retrieve registers: expected %zu elements" ", got %u", n_regs, args.reps); return -1; @@ -243,7 +242,6 @@ static int get_generic_regs(CPUState *cpu, hv_register_assoc *assocs, for (i = 0; i < n_regs; i++) { assocs[i].value = values[i]; } - g_free(values); return 0; } @@ -1696,6 +1694,19 @@ void mshv_arch_init_vcpu(CPUState *cpu) { X86CPU *x86_cpu = X86_CPU(cpu); CPUX86State *env = &x86_cpu->env; + AccelCPUState *state = cpu->accel; + size_t page = HV_HYP_PAGE_SIZE; + void *mem = qemu_memalign(page, 2 * page); + + /* sanity check, to make sure we don't overflow the page */ + QEMU_BUILD_BUG_ON((MAX_REGISTER_COUNT + * sizeof(hv_register_assoc) + + sizeof(hv_input_get_vp_registers) + > HV_HYP_PAGE_SIZE)); + + state->hvcall_args.base = mem; + state->hvcall_args.input_page = mem; + state->hvcall_args.output_page = (uint8_t *)mem + page; env->emu_mmio_buf = g_new(char, 4096); } @@ -1704,7 +1715,10 @@ void mshv_arch_destroy_vcpu(CPUState *cpu) { X86CPU *x86_cpu = X86_CPU(cpu); CPUX86State *env = &x86_cpu->env; + AccelCPUState *state = cpu->accel; + g_free(state->hvcall_args.base); + state->hvcall_args = (MshvHvCallArgs){0}; g_clear_pointer(&env->emu_mmio_buf, g_free); } -- 2.51.0