Host shouldn't map guest memory not shared with it. These
functions allow kvmtool in a future patch to toggle the mapping
depending on the sharing status, even if it changes.
Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx>
---
include/kvm/kvm.h | 4 +
kvm.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 187 insertions(+)
diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h
index 6192f6c..66b5664 100644
--- a/include/kvm/kvm.h
+++ b/include/kvm/kvm.h
@@ -220,6 +220,10 @@ static inline bool kvm__arch_has_cfg_ram_address(void)
void *guest_flat_to_host(struct kvm *kvm, u64 offset);
u64 host_to_guest_flat(struct kvm *kvm, void *ptr);
+void map_guest_range(struct kvm *kvm, u64 gpa, u64 size);
+void unmap_guest_range(struct kvm *kvm, u64 gpa, u64 size);
+void map_guest(struct kvm *kvm);
+void unmap_guest(struct kvm *kvm);
bool kvm__arch_load_kernel_image(struct kvm *kvm, int fd_kernel, int fd_initrd,
const char *kernel_cmdline);
diff --git a/kvm.c b/kvm.c
index a0bddf4..66e6a8e 100644
--- a/kvm.c
+++ b/kvm.c
@@ -462,6 +462,189 @@ int kvm__for_each_mem_bank(struct kvm *kvm, enum kvm_mem_type type,
return ret;
}
+static void *_mmap(void *addr, size_t len, int prot, int flags, int fd, off_t offset)
+{
+ return mmap(addr, len, prot, flags | MAP_FIXED, fd, offset);
+}
+
+static int _munmap(void *addr, size_t len)
+{
+ if (mmap(addr, len, PROT_NONE, MAP_SHARED | MAP_FIXED | MAP_ANON, -1, 0) != MAP_FAILED)
+ return 0;
+
+ return -EFAULT;
+}
+
+struct bank_range {
+ u64 gpa;
+ u64 size;
+};
+
+static bool is_bank_range(struct kvm_mem_bank *bank, struct bank_range *range)
+{
+ u64 bank_start = bank->guest_phys_addr;
+ u64 bank_end = bank_start + bank->size;
+ u64 gpa_end = range->gpa + range->size;
+
+ if (range->gpa < bank_start || range->gpa >= bank_end)
+ return false;
+
+ if (gpa_end > bank_end || gpa_end <= bank_start) {
+ pr_warning("%s invalid guest range", __func__);
+ return false;
+ }
+
+ return true;
+}
+
+static int map_bank_range(struct kvm *kvm, struct kvm_mem_bank *bank, void *data)
+{
+ struct bank_range *range = data;
+ u64 gpa_offset;
+ u64 map_offset;
+ u64 hva;
+ void *mapping;
+
+ if (!is_bank_range(bank, range))
+ return 0;
+
+ gpa_offset = range->gpa - bank->guest_phys_addr;
+ map_offset = bank->memfd_offset + gpa_offset;
+ hva = (u64) bank->host_addr + gpa_offset;
+
+ BUG_ON(map_offset > bank->memfd_offset + bank->size);
+ BUG_ON(map_offset < bank->memfd_offset);
+ BUG_ON(hva < (u64)bank->host_addr);
+ BUG_ON(!bank->memfd);
+
+ mapping = _mmap((void *)hva, range->size, PROT_RW, MAP_SHARED, bank->memfd, map_offset);
+ if (mapping == MAP_FAILED || mapping != (void *)hva)
+ pr_warning("%s gpa 0x%llx (size: %llu) at hva 0x%llx failed with mapping 0x%llx",
+ __func__,
+ (unsigned long long)range->gpa,
+ (unsigned long long)range->size,
+ (unsigned long long)hva,
+ (unsigned long long)mapping);
+
+ /* Do not proceed to trying to map the other banks. */
+ return 1;
+}
+
+static int unmap_bank_range(struct kvm *kvm, struct kvm_mem_bank *bank, void *data)
+{
+ struct bank_range *range = data;
+ u64 gpa_offset;
+ u64 hva;
+ int ret;
+
+ if (!is_bank_range(bank, range))
+ return 0;
+
+ gpa_offset = range->gpa - bank->guest_phys_addr;
+ hva = (u64)bank->host_addr + gpa_offset;
+
+ BUG_ON(hva < (u64)bank->host_addr);
+ BUG_ON(!bank->memfd);
+
+ ret = _munmap((void *)hva, range->size);
+ if (ret)
+ pr_warning("%s gpa 0x%llx (size: %llu) at hva 0x%llx failed with error %d",
+ __func__,
+ (unsigned long long)range->gpa,
+ (unsigned long long)range->size,
+ (unsigned long long)hva,
+ ret);
+
+ /* Do not proceed to trying to unmap the other banks. */
+ return 1;
+}
+
+static int map_bank(struct kvm *kvm, struct kvm_mem_bank *bank, void *data)
+{
+ void *mapping;
+
+ BUG_ON(!bank->memfd);
+
+ pr_debug("%s hva 0x%llx (size: %llu) of memfd %d (offset %llu)",
+ __func__,
+ (unsigned long long)bank->host_addr,
+ (unsigned long long)bank->size,
+ bank->memfd,
+ (unsigned long long)bank->memfd_offset);
+
+ mapping = _mmap(bank->host_addr, bank->size, PROT_RW, MAP_SHARED, bank->memfd, bank->memfd_offset);
+ if (!mapping || mapping != bank->host_addr)
+ pr_warning("%s hva 0x%llx (size: %llu) failed with return 0x%llx",
+ __func__,
+ (unsigned long long)bank->host_addr,
+ (unsigned long long)bank->size,
+ (unsigned long long)mapping);
+ return 0;
+}
+
+static int unmap_bank(struct kvm *kvm, struct kvm_mem_bank *bank, void *data)
+{
+ int ret;
+
+ pr_debug("%s hva 0x%llx (size: %llu)",
+ __func__,
+ (unsigned long long)bank->host_addr,
+ (unsigned long long)bank->size);
+
+ ret = _munmap(bank->host_addr, bank->size);
+ if (ret)
+ pr_warning("%s hva 0x%llx (size: %llu) failed with error %d",
+ __func__,
+ (unsigned long long)bank->host_addr,
+ (unsigned long long)bank->size,
+ ret);
+ return 0;
+}
+
+void map_guest_range(struct kvm *kvm, u64 gpa, u64 size)
+{
+ struct bank_range range = { .gpa = gpa, .size = size };
+ int ret;
+
+ ret = kvm__for_each_mem_bank(kvm, KVM_MEM_TYPE_RAM|KVM_MEM_TYPE_DEVICE,
+ map_bank_range, &range);
+
+ if (!ret)
+ pr_warning("%s gpa 0x%llx (size: %llu) found no matches",
+ __func__,
+ (unsigned long long)gpa,
+ (unsigned long long)size);
+}
+
+void unmap_guest_range(struct kvm *kvm, u64 gpa, u64 size)
+{
+ struct bank_range range = { .gpa = gpa, .size = size };
+ int ret;
+
+ ret = kvm__for_each_mem_bank(kvm, KVM_MEM_TYPE_RAM|KVM_MEM_TYPE_DEVICE,
+ unmap_bank_range, &range);
+
+ if (!ret)
+ pr_warning("%s gpa 0x%llx (size: %llu) found no matches",
+ __func__,
+ (unsigned long long)gpa,
+ (unsigned long long)size);
+
+ return;
+}
+
+void map_guest(struct kvm *kvm)
+{
+ kvm__for_each_mem_bank(kvm, KVM_MEM_TYPE_RAM|KVM_MEM_TYPE_DEVICE,
+ map_bank, NULL);
+}
+
+void unmap_guest(struct kvm *kvm)
+{
+ kvm__for_each_mem_bank(kvm, KVM_MEM_TYPE_RAM|KVM_MEM_TYPE_DEVICE,
+ unmap_bank, NULL);
+}
+
int kvm__recommended_cpus(struct kvm *kvm)
{
int ret;
--
2.39.0.rc0.267.gcb52ba06e7-goog
