[PATCH 2/2] PCIPT: direct mmio

Ben-Ami Yassour
2008-07-16T13:22:21Z

Enable a guest to access a device's memory mapped I/O regions directly.
When the guest changes the I/O memory mappings for a passthrough device,
send the updated mmio region to the kernel.

Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com>
Signed-off-by: Muli Ben-Yehuda <muli@il.ibm.com>
---
libkvm/libkvm.c | 24 ++++++++----
qemu/hw/pci-passthrough.c | 88 +++++++++++---------------------------------
qemu/hw/pci-passthrough.h | 2 +
3 files changed, 40 insertions(+), 74 deletions(-)

diff --git a/libkvm/libkvm.c b/libkvm/libkvm.c
index a49cbdc..35bc411 100644
--- a/libkvm/libkvm.c
+++ b/libkvm/libkvm.c
@@ -400,7 +400,7 @@ void *kvm_create_userspace_phys_mem(kvm_context_t kvm, unsigned long phys_start,
{
int r;
int prot = PROT_READ;
- void *ptr;
+ void *ptr = NULL;
struct kvm_userspace_memory_region memory = {
.memory_size = len,
.guest_phys_addr = phys_start,
@@ -410,16 +410,24 @@ void *kvm_create_userspace_phys_mem(kvm_context_t kvm, unsigned long phys_start,
if (writable)
prot |= PROT_WRITE;

- ptr = mmap(NULL, len, prot, MAP_ANONYMOUS | MAP_SHARED, -1, 0);
- if (ptr == MAP_FAILED) {
- fprintf(stderr, "create_userspace_phys_mem: %s", strerror(errno));
- return 0;
- }
+ if (len > 0) {
+ ptr = mmap(NULL, len, prot, MAP_ANONYMOUS | MAP_SHARED, -1, 0);
+ if (ptr == MAP_FAILED) {
+ fprintf(stderr, "create_userspace_phys_mem: %s",
+ strerror(errno));
+ return 0;
+ }

- memset(ptr, 0, len);
+ memset(ptr, 0, len);
+ }

memory.userspace_addr = (unsigned long)ptr;
- memory.slot = get_free_slot(kvm);
+
+ if (len > 0)
+ memory.slot = get_free_slot(kvm);
+ else
+ memory.slot = get_slot(phys_start);
+
r = ioctl(kvm->vm_fd, KVM_SET_USER_MEMORY_REGION, &memory);
if (r == -1) {
fprintf(stderr, "create_userspace_phys_mem: %s", strerror(errno));
diff --git a/qemu/hw/pci-passthrough.c b/qemu/hw/pci-passthrough.c
index 250d7ef..08e339d 100644
--- a/qemu/hw/pci-passthrough.c
+++ b/qemu/hw/pci-passthrough.c
@@ -51,59 +51,6 @@ extern FILE *logfile;
#define DEBUG(fmt, args...)
#endif

-#define pt_mmio_write(suffix, type) \
-static void pt_mmio_write##suffix(void *opaque, target_phys_addr_t e_phys, \
- uint32_t value) \
-{ \
- pt_region_t *r_access = (pt_region_t *)opaque; \
- void *r_virt = (uint8_t *)r_access->r_virtbase + \
- (e_phys - r_access->e_physbase); \
- if (r_access->debug & PT_DEBUG_MMIO) { \
- fprintf(logfile, "pt_mmio_write" #suffix \
- ": e_physbase=%p e_phys=%p r_virt=%p value=%08x\n", \
- (void *)r_access->e_physbase, (void *)e_phys, \
- r_virt, value); \
- } \
- *(type *)r_virt = (type)value; \
-}
-
-pt_mmio_write(b, uint8_t)
-pt_mmio_write(w, uint16_t)
-pt_mmio_write(l, uint32_t)
-
-#define pt_mmio_read(suffix, type) \
-static uint32_t pt_mmio_read##suffix(void *opaque, target_phys_addr_t e_phys) \
-{ \
- pt_region_t *r_access = (pt_region_t *)opaque; \
- void *r_virt = (uint8_t *)r_access->r_virtbase + \
- (e_phys - r_access->e_physbase); \
- uint32_t value = (uint32_t) (*(type *) r_virt); \
- if (r_access->debug & PT_DEBUG_MMIO) { \
- fprintf(logfile, \
- "pt_mmio_read" #suffix ": e_physbase=%p " \
- "e_phys=%p r_virt=%p value=%08x\n", \
- (void *)r_access->e_physbase, \
- (void *)e_phys, r_virt, value); \
- } \
- return value; \
-}
-
-pt_mmio_read(b, uint8_t)
-pt_mmio_read(w, uint16_t)
-pt_mmio_read(l, uint32_t)
-
-CPUReadMemoryFunc *pt_mmio_read_cb[3] = {
- pt_mmio_readb,
- pt_mmio_readw,
- pt_mmio_readl
-};
-
-CPUWriteMemoryFunc *pt_mmio_write_cb[3] = {
- pt_mmio_writeb,
- pt_mmio_writew,
- pt_mmio_writel
-};
-
#define pt_ioport_write(suffix) \
static void pt_ioport_write##suffix(void *opaque, uint32_t addr, uint32_t value) \
{ \
@@ -145,20 +92,32 @@ pt_ioport_read(b)
pt_ioport_read(w)
pt_ioport_read(l)

-static void pt_iomem_map(PCIDevice *d, int region_num,
- uint32_t e_phys, uint32_t e_size, int type)
+void pt_iomem_map(PCIDevice * pci_dev, int region_num, uint32_t e_phys,
+ uint32_t e_size, int type)
{
- pt_dev_t *r_dev = (pt_dev_t *) d;
-
- r_dev->v_addrs[region_num].e_physbase = e_phys;
+ pt_dev_t *r_dev = (pt_dev_t *) pci_dev;
+ pt_region_t *region = &r_dev->v_addrs[region_num];
+ int first_map = (region->e_size == 0);
+ int ret = 0;

DEBUG("e_phys=%08x r_virt=%p type=%d len=%08x region_num=%d \n",
e_phys, r_dev->v_addrs[region_num].r_virtbase, type, e_size,
region_num);

- cpu_register_physical_memory(e_phys,
- r_dev->dev.io_regions[region_num].size,
- r_dev->v_addrs[region_num].memory_index);
+ region->e_physbase = e_phys;
+ region->e_size = e_size;
+
+ if (!first_map)
+ kvm_destroy_phys_mem(kvm_context, e_phys, e_size);
+
+ if (e_size > 0)
+ ret = kvm_register_userspace_phys_mem(kvm_context,
+ e_phys,
+ region->r_virtbase,
+ e_size,
+ 0);
+ if (ret != 0)
+ fprintf(logfile, "Error: create new mapping failed\n");
}

static void pt_ioport_map(PCIDevice *pci_dev, int region_num,
@@ -295,6 +254,8 @@ static int pt_register_regions(pci_region_t *io_regions,
(uint32_t) (cur_region->base_addr));
return -1;
}
+ pci_dev->v_addrs[i].r_size = cur_region->size;
+ pci_dev->v_addrs[i].e_size = 0;

/* add offset */
pci_dev->v_addrs[i].r_virtbase +=
@@ -304,11 +265,6 @@ static int pt_register_regions(pci_region_t *io_regions,
cur_region->size, t,
pt_iomem_map);

- pci_dev->v_addrs[i].memory_index =
- cpu_register_io_memory(0, pt_mmio_read_cb,
- pt_mmio_write_cb,
- (void *) &(pci_dev->v_addrs[i]));
-
continue;
}
/* handle port io regions */
diff --git a/qemu/hw/pci-passthrough.h b/qemu/hw/pci-passthrough.h
index 60df017..7a98b0e 100644
--- a/qemu/hw/pci-passthrough.h
+++ b/qemu/hw/pci-passthrough.h
@@ -65,6 +65,8 @@ typedef struct pt_region_s {
uint32_t memory_index;
void *r_virtbase; /* mmapped access address */
int num; /* our index within v_addrs[] */
+ uint32_t e_size; /* emulated size of region in bytes */
+ uint32_t r_size; /* real size of region in bytes */
uint32_t debug;
} pt_region_t;

--
1.5.6