The command is used for encrypting the guest memory region using the VM encryption key (VEK) created from LAUNCH_START. Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx> --- arch/x86/kvm/svm.c | 150 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index b5fa8c0..62c2b22 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -38,6 +38,8 @@ #include <linux/hashtable.h> #include <linux/psp-sev.h> #include <linux/file.h> +#include <linux/pagemap.h> +#include <linux/swap.h> #include <asm/apic.h> #include <asm/perf_event.h> @@ -502,6 +504,7 @@ static void sev_deactivate_handle(struct kvm *kvm); static void sev_decommission_handle(struct kvm *kvm); static int sev_asid_new(void); static void sev_asid_free(int asid); +#define __sev_page_pa(x) ((page_to_pfn(x) << PAGE_SHIFT) | sme_me_mask) static bool kvm_sev_enabled(void) { @@ -5775,6 +5778,149 @@ static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp) return ret; } +static struct page **sev_pin_memory(unsigned long uaddr, unsigned long ulen, + unsigned long *n) +{ + struct page **pages; + int first, last; + unsigned long npages, pinned; + + /* Get number of pages */ + first = (uaddr & PAGE_MASK) >> PAGE_SHIFT; + last = ((uaddr + ulen - 1) & PAGE_MASK) >> PAGE_SHIFT; + npages = (last - first + 1); + + pages = kzalloc(npages * sizeof(struct page *), GFP_KERNEL); + if (!pages) + return NULL; + + /* pin the user virtual address */ + down_read(¤t->mm->mmap_sem); + pinned = get_user_pages_fast(uaddr, npages, 1, pages); + up_read(¤t->mm->mmap_sem); + if (pinned != npages) { + printk(KERN_ERR "SEV: failed to pin %ld pages (got %ld)\n", + npages, pinned); + goto err; + } + + *n = npages; + return pages; +err: + if (pinned > 0) + release_pages(pages, pinned, 0); + kfree(pages); + + return NULL; +} + +static void sev_unpin_memory(struct page **pages, unsigned long npages) +{ + release_pages(pages, npages, 0); + kfree(pages); +} + +static void sev_clflush_pages(struct page *pages[], int num_pages) +{ + unsigned long i; + uint8_t *page_virtual; + + if (num_pages == 0 || pages == NULL) + return; + + for (i = 0; i < num_pages; i++) { + page_virtual = kmap_atomic(pages[i]); + clflush_cache_range(page_virtual, PAGE_SIZE); + kunmap_atomic(page_virtual); + } +} + +static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp) +{ + struct page **inpages; + unsigned long uaddr, ulen; + int i, len, ret, offset; + unsigned long nr_pages; + struct kvm_sev_launch_update_data params; + struct sev_data_launch_update_data *data; + + if (!sev_guest(kvm)) + return -EINVAL; + + /* Get the parameters from the user */ + ret = -EFAULT; + if (copy_from_user(¶ms, (void *)argp->data, + sizeof(struct kvm_sev_launch_update_data))) + goto err_1; + + uaddr = params.address; + ulen = params.length; + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) { + ret = -ENOMEM; + goto err_1; + } + + /* pin user pages */ + inpages = sev_pin_memory(params.address, params.length, &nr_pages); + if (!inpages) { + ret = -ENOMEM; + goto err_2; + } + + /* invalidate the cache line for these pages to ensure that DRAM + * has recent content before calling the SEV commands to perform + * the encryption. + */ + sev_clflush_pages(inpages, nr_pages); + + /* the array of pages returned by get_user_pages() is a page-aligned + * memory. Since the user buffer is probably not page-aligned, we need + * to calculate the offset within a page for first update entry. + */ + offset = uaddr & (PAGE_SIZE - 1); + len = min_t(size_t, (PAGE_SIZE - offset), ulen); + ulen -= len; + + /* update first page - + * special care need to be taken for the first page because we might + * be dealing with offset within the page + */ + data->handle = sev_get_handle(kvm); + data->length = len; + data->address = __sev_page_pa(inpages[0]) + offset; + ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_DATA, + data, &argp->error); + if (ret) + goto err_3; + + /* update remaining pages */ + for (i = 1; i < nr_pages; i++) { + + len = min_t(size_t, PAGE_SIZE, ulen); + ulen -= len; + data->length = len; + data->address = __sev_page_pa(inpages[i]); + ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_DATA, + data, &argp->error); + if (ret) + goto err_3; + } + + /* mark pages dirty */ + for (i = 0; i < nr_pages; i++) { + set_page_dirty_lock(inpages[i]); + mark_page_accessed(inpages[i]); + } +err_3: + sev_unpin_memory(inpages, nr_pages); +err_2: + kfree(data); +err_1: + return ret; +} + static int amd_memory_encryption_cmd(struct kvm *kvm, void __user *argp) { int r = -ENOTTY; @@ -5790,6 +5936,10 @@ static int amd_memory_encryption_cmd(struct kvm *kvm, void __user *argp) r = sev_launch_start(kvm, &sev_cmd); break; } + case KVM_SEV_LAUNCH_UPDATE_DATA: { + r = sev_launch_update_data(kvm, &sev_cmd); + break; + } default: break; }