From 6768f733a8e0aa0821b96e8312e77449de15eaf0 Mon Sep 17 00:00:00 2001 From: Pekka Enberg Date: Mon, 6 Jun 2011 16:48:50 +0300 Subject: [PATCH] kvm tools, vesa: Use guest-mapped memory for framebuffer This patch converts hw/vesa.c to use guest-mapped memory for framebuffer and drops the slow MMIO emulation. This speeds up framebuffer accesses considerably. Please note that this can be optimized even more with the KVM_GET_DIRTY_LOG ioctl() as explained by Alexander Graf. Cc: Alexander Graf Cc: Cyrill Gorcunov Cc: Ingo Molnar Cc: John Floren Cc: Sasha Levin Signed-off-by: Pekka Enberg --- tools/kvm/hw/vesa.c | 17 +++++------------ tools/kvm/include/kvm/kvm.h | 9 ++++++++- tools/kvm/kvm.c | 15 ++++++++++----- 3 files changed, 23 insertions(+), 18 deletions(-) diff --git a/tools/kvm/hw/vesa.c b/tools/kvm/hw/vesa.c index 48d31cea301f..71322fc2da5b 100644 --- a/tools/kvm/hw/vesa.c +++ b/tools/kvm/hw/vesa.c @@ -8,6 +8,7 @@ #include "kvm/irq.h" #include "kvm/kvm.h" #include "kvm/pci.h" +#include #include #include @@ -40,14 +41,6 @@ static struct pci_device_header vesa_pci_device = { .bar[1] = VESA_MEM_ADDR | PCI_BASE_ADDRESS_SPACE_MEMORY, }; -static void vesa_mmio_callback(u64 addr, u8 *data, u32 len, u8 is_write) -{ - if (!is_write) - return; - - fb__write(addr, data, len); -} - static struct framebuffer vesafb; struct framebuffer *vesa__init(struct kvm *kvm) @@ -65,12 +58,12 @@ struct framebuffer *vesa__init(struct kvm *kvm) vesa_pci_device.bar[0] = vesa_base_addr | PCI_BASE_ADDRESS_SPACE_IO; pci__register(&vesa_pci_device, dev); - kvm__register_mmio(kvm, VESA_MEM_ADDR, VESA_MEM_SIZE, &vesa_mmio_callback); - - mem = calloc(1, VESA_MEM_SIZE); - if (!mem) + mem = mmap(NULL, VESA_MEM_SIZE, PROT_RW, MAP_ANON_NORESERVE, -1, 0); + if (mem == MAP_FAILED) return NULL; + kvm__register_mem(kvm, VESA_MEM_ADDR, VESA_MEM_SIZE, mem); + vesafb = (struct framebuffer) { .width = VESA_WIDTH, .height = VESA_HEIGHT, diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h index 55551de30b08..4eeed87f2787 100644 --- a/tools/kvm/include/kvm/kvm.h +++ b/tools/kvm/include/kvm/kvm.h @@ -8,7 +8,11 @@ #include #define KVM_NR_CPUS (255) -#define KVM_32BIT_GAP_SIZE (512 << 20) + +/* + * The hole includes VESA framebuffer and PCI memory. + */ +#define KVM_32BIT_GAP_SIZE (768 << 20) #define KVM_32BIT_GAP_START ((1ULL << 32) - KVM_32BIT_GAP_SIZE) #define SIGKVMEXIT (SIGRTMIN + 0) @@ -21,6 +25,8 @@ struct kvm { int nrcpus; /* Number of cpus to run */ + u32 mem_slots; /* for KVM_SET_USER_MEMORY_REGION */ + u64 ram_size; void *ram_start; @@ -49,6 +55,7 @@ void kvm__stop_timer(struct kvm *kvm); void kvm__irq_line(struct kvm *kvm, int irq, int level); bool kvm__emulate_io(struct kvm *kvm, u16 port, void *data, int direction, int size, u32 count); bool kvm__emulate_mmio(struct kvm *kvm, u64 phys_addr, u8 *data, u32 len, u8 is_write); +void kvm__register_mem(struct kvm *kvm, u64 guest_phys, u64 size, void *userspace_addr); bool kvm__register_mmio(struct kvm *kvm, u64 phys_addr, u64 phys_addr_len, void (*kvm_mmio_callback_fn)(u64 addr, u8 *data, u32 len, u8 is_write)); bool kvm__deregister_mmio(struct kvm *kvm, u64 phys_addr); void kvm__pause(void); diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c index 54e3203df0ba..2c56a7928033 100644 --- a/tools/kvm/kvm.c +++ b/tools/kvm/kvm.c @@ -162,13 +162,18 @@ static bool kvm__cpu_supports_vm(void) return regs.ecx & (1 << feature); } -static void kvm_register_mem_slot(struct kvm *kvm, u32 slot, u64 guest_phys, u64 size, void *userspace_addr) +/* + * Note: KVM_SET_USER_MEMORY_REGION assumes that we don't pass overlapping + * memory regions to it. Therefore, be careful if you use this function for + * registering memory regions for emulating hardware. + */ +void kvm__register_mem(struct kvm *kvm, u64 guest_phys, u64 size, void *userspace_addr) { struct kvm_userspace_memory_region mem; int ret; mem = (struct kvm_userspace_memory_region) { - .slot = slot, + .slot = kvm->mem_slots++, .guest_phys_addr = guest_phys, .memory_size = size, .userspace_addr = (unsigned long)userspace_addr, @@ -200,7 +205,7 @@ void kvm__init_ram(struct kvm *kvm) phys_size = kvm->ram_size; host_mem = kvm->ram_start; - kvm_register_mem_slot(kvm, 0, phys_start, phys_size, host_mem); + kvm__register_mem(kvm, phys_start, phys_size, host_mem); } else { /* First RAM range from zero to the PCI gap: */ @@ -208,7 +213,7 @@ void kvm__init_ram(struct kvm *kvm) phys_size = KVM_32BIT_GAP_START; host_mem = kvm->ram_start; - kvm_register_mem_slot(kvm, 0, phys_start, phys_size, host_mem); + kvm__register_mem(kvm, phys_start, phys_size, host_mem); /* Second RAM range from 4GB to the end of RAM: */ @@ -216,7 +221,7 @@ void kvm__init_ram(struct kvm *kvm) phys_size = kvm->ram_size - phys_size; host_mem = kvm->ram_start + phys_start; - kvm_register_mem_slot(kvm, 1, phys_start, phys_size, host_mem); + kvm__register_mem(kvm, phys_start, phys_size, host_mem); } } -- 2.39.5