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KVM: SVM: Add support for KVM_SEV_LAUNCH_UPDATE_DATA command

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The command is used for encrypting the guest memory region using the VM
encryption key (VEK) created during KVM_SEV_LAUNCH_START.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Improvements-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
This commit is contained in:
Brijesh Singh 2017-12-04 10:57:35 -06:00
parent 59414c9892
commit 89c5058090
2 changed files with 190 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/include/asm/kvm_host.h
View File

@ -752,6 +752,7 @@ struct kvm_sev_info {
unsigned int asid; /* ASID used for this guest */
unsigned int handle; /* SEV firmware handle */
int fd; /* SEV device fd */
unsigned long pages_locked; /* Number of pages locked */
};
struct kvm_arch {

191
arch/x86/kvm/svm.c
View File

@ -39,6 +39,8 @@
#include <linux/frame.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>
@ -331,6 +333,7 @@ enum {
static unsigned int max_sev_asid;
static unsigned int min_sev_asid;
static unsigned long *sev_asid_bitmap;
#define __sme_page_pa(x) __sme_set(page_to_pfn(x) << PAGE_SHIFT)
static inline bool svm_sev_enabled(void)
{
@ -1569,6 +1572,83 @@ static void sev_unbind_asid(struct kvm *kvm, unsigned int handle)
kfree(decommission);
}
static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr,
unsigned long ulen, unsigned long *n,
int write)
{
struct kvm_sev_info *sev = &kvm->arch.sev_info;
unsigned long npages, npinned, size;
unsigned long locked, lock_limit;
struct page **pages;
int first, last;
/* Calculate number of pages. */
first = (uaddr & PAGE_MASK) >> PAGE_SHIFT;
last = ((uaddr + ulen - 1) & PAGE_MASK) >> PAGE_SHIFT;
npages = (last - first + 1);
locked = sev->pages_locked + npages;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
pr_err("SEV: %lu locked pages exceed the lock limit of %lu.\n", locked, lock_limit);
return NULL;
}
/* Avoid using vmalloc for smaller buffers. */
size = npages * sizeof(struct page *);
if (size > PAGE_SIZE)
pages = vmalloc(size);
else
pages = kmalloc(size, GFP_KERNEL);
if (!pages)
return NULL;
/* Pin the user virtual address. */
npinned = get_user_pages_fast(uaddr, npages, write ? FOLL_WRITE : 0, pages);
if (npinned != npages) {
pr_err("SEV: Failure locking %lu pages.\n", npages);
goto err;
}
*n = npages;
sev->pages_locked = locked;
return pages;
err:
if (npinned > 0)
release_pages(pages, npinned);
kvfree(pages);
return NULL;
}
static void sev_unpin_memory(struct kvm *kvm, struct page **pages,
unsigned long npages)
{
struct kvm_sev_info *sev = &kvm->arch.sev_info;
release_pages(pages, npages);
kvfree(pages);
sev->pages_locked -= npages;
}
static void sev_clflush_pages(struct page *pages[], unsigned long npages)
{
uint8_t *page_virtual;
unsigned long i;
if (npages == 0 || pages == NULL)
return;
for (i = 0; i < npages; i++) {
page_virtual = kmap_atomic(pages[i]);
clflush_cache_range(page_virtual, PAGE_SIZE);
kunmap_atomic(page_virtual);
}
}
static void sev_vm_destroy(struct kvm *kvm)
{
struct kvm_sev_info *sev = &kvm->arch.sev_info;
@ -5767,7 +5847,7 @@ static int sev_bind_asid(struct kvm *kvm, unsigned int handle, int *error)
return ret;
}
static int sev_issue_cmd(int fd, int id, void *data, int *error)
static int __sev_issue_cmd(int fd, int id, void *data, int *error)
{
struct fd f;
int ret;
@ -5782,6 +5862,13 @@ static int sev_issue_cmd(int fd, int id, void *data, int *error)
return ret;
}
static int sev_issue_cmd(struct kvm *kvm, int id, void *data, int *error)
{
struct kvm_sev_info *sev = &kvm->arch.sev_info;
return __sev_issue_cmd(sev->fd, id, data, error);
}
static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
struct kvm_sev_info *sev = &kvm->arch.sev_info;
@ -5829,7 +5916,7 @@ static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
start->policy = params.policy;
/* create memory encryption context */
ret = sev_issue_cmd(argp->sev_fd, SEV_CMD_LAUNCH_START, start, error);
ret = __sev_issue_cmd(argp->sev_fd, SEV_CMD_LAUNCH_START, start, error);
if (ret)
goto e_free_session;
@ -5858,6 +5945,103 @@ static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
return ret;
}
static int get_num_contig_pages(int idx, struct page **inpages,
unsigned long npages)
{
unsigned long paddr, next_paddr;
int i = idx + 1, pages = 1;
/* find the number of contiguous pages starting from idx */
paddr = __sme_page_pa(inpages[idx]);
while (i < npages) {
next_paddr = __sme_page_pa(inpages[i++]);
if ((paddr + PAGE_SIZE) == next_paddr) {
pages++;
paddr = next_paddr;
continue;
}
break;
}
return pages;
}
static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
unsigned long vaddr, vaddr_end, next_vaddr, npages, size;
struct kvm_sev_info *sev = &kvm->arch.sev_info;
struct kvm_sev_launch_update_data params;
struct sev_data_launch_update_data *data;
struct page **inpages;
int i, ret, pages;
if (!sev_guest(kvm))
return -ENOTTY;
if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data, sizeof(params)))
return -EFAULT;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
vaddr = params.uaddr;
size = params.len;
vaddr_end = vaddr + size;
/* Lock the user memory. */
inpages = sev_pin_memory(kvm, vaddr, size, &npages, 1);
if (!inpages) {
ret = -ENOMEM;
goto e_free;
}
/*
* The LAUNCH_UPDATE command will perform in-place encryption of the
* memory content (i.e it will write the same memory region with C=1).
* It's possible that the cache may contain the data with C=0, i.e.,
* unencrypted so invalidate it first.
*/
sev_clflush_pages(inpages, npages);
for (i = 0; vaddr < vaddr_end; vaddr = next_vaddr, i += pages) {
int offset, len;
/*
* If the user buffer is not page-aligned, calculate the offset
* within the page.
*/
offset = vaddr & (PAGE_SIZE - 1);
/* Calculate the number of pages that can be encrypted in one go. */
pages = get_num_contig_pages(i, inpages, npages);
len = min_t(size_t, ((pages * PAGE_SIZE) - offset), size);
data->handle = sev->handle;
data->len = len;
data->address = __sme_page_pa(inpages[i]) + offset;
ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_DATA, data, &argp->error);
if (ret)
goto e_unpin;
size -= len;
next_vaddr = vaddr + len;
}
e_unpin:
/* content of memory is updated, mark pages dirty */
for (i = 0; i < npages; i++) {
set_page_dirty_lock(inpages[i]);
mark_page_accessed(inpages[i]);
}
/* unlock the user pages */
sev_unpin_memory(kvm, inpages, npages);
e_free:
kfree(data);
return ret;
}
static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
{
struct kvm_sev_cmd sev_cmd;
@ -5878,6 +6062,9 @@ static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
case KVM_SEV_LAUNCH_START:
r = sev_launch_start(kvm, &sev_cmd);
break;
case KVM_SEV_LAUNCH_UPDATE_DATA:
r = sev_launch_update_data(kvm, &sev_cmd);
break;
default:
r = -EINVAL;
goto out;