Re: [RFC PATCH v2 26/32] kvm: svm: Add support for SEV LAUNCH_UPDATE_DATA command

2017-03-16 Thread Brijesh Singh 


On 03/16/2017 05:48 AM, Paolo Bonzini wrote:



On 02/03/2017 16:17, Brijesh Singh wrote:

+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(>mm->mmap_sem);
+   pinned = get_user_pages_fast(uaddr, npages, 1, pages);
+   up_read(>mm->mmap_sem);


get_user_pages_fast, like get_user_pages_unlocked, must be called
without mmap_sem held.


Sure.




+   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;
+}

+   /* 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
+*/


No need to special case the first page; just set "offset = 0" inside the
loop after the first iteration.



Will do.

-Brijesh
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Re: [RFC PATCH v2 26/32] kvm: svm: Add support for SEV LAUNCH_UPDATE_DATA command

2017-03-16 Thread Paolo Bonzini 


On 02/03/2017 16:17, Brijesh Singh wrote:
> +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(>mm->mmap_sem);
> + pinned = get_user_pages_fast(uaddr, npages, 1, pages);
> + up_read(>mm->mmap_sem);

get_user_pages_fast, like get_user_pages_unlocked, must be called
without mmap_sem held.

> + 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;
> +}
>
> + /* 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
> +  */

No need to special case the first page; just set "offset = 0" inside the
loop after the first iteration.

Paolo

> + 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, >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, >error);
> + if (ret)
> + goto err_3;
> + }

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[RFC PATCH v2 26/32] kvm: svm: Add support for SEV LAUNCH_UPDATE_DATA command

2017-03-02 Thread Brijesh Singh 
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 
---
 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 
 #include 
 #include 
+#include 
+#include 
 
 #include 
 #include 
@@ -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(>mm->mmap_sem);
+   pinned = get_user_pages_fast(uaddr, npages, 1, pages);
+   up_read(>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(, (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, _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, >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,
+