#include <linux/pci.h>
#include <linux/gfp.h>
#include <linux/memblock.h>
- #include <linux/syscore_ops.h>
#include <xen/xen.h>
#include <xen/interface/xen.h>
.wbinvd = native_wbinvd,
.read_msr = native_read_msr_safe,
- .rdmsr_regs = native_rdmsr_safe_regs,
.write_msr = xen_write_msr_safe,
- .wrmsr_regs = native_wrmsr_safe_regs,
.read_tsc = native_read_tsc,
.read_pmc = native_read_pmc,
#endif
}
- #ifdef CONFIG_XEN_PVHVM
- /*
- * The pfn containing the shared_info is located somewhere in RAM. This
- * will cause trouble if the current kernel is doing a kexec boot into a
- * new kernel. The new kernel (and its startup code) can not know where
- * the pfn is, so it can not reserve the page. The hypervisor will
- * continue to update the pfn, and as a result memory corruption occours
- * in the new kernel.
- *
- * One way to work around this issue is to allocate a page in the
- * xen-platform pci device's BAR memory range. But pci init is done very
- * late and the shared_info page is already in use very early to read
- * the pvclock. So moving the pfn from RAM to MMIO is racy because some
- * code paths on other vcpus could access the pfn during the small
- * window when the old pfn is moved to the new pfn. There is even a
- * small window were the old pfn is not backed by a mfn, and during that
- * time all reads return -1.
- *
- * Because it is not known upfront where the MMIO region is located it
- * can not be used right from the start in xen_hvm_init_shared_info.
- *
- * To minimise trouble the move of the pfn is done shortly before kexec.
- * This does not eliminate the race because all vcpus are still online
- * when the syscore_ops will be called. But hopefully there is no work
- * pending at this point in time. Also the syscore_op is run last which
- * reduces the risk further.
- */
-
- static struct shared_info *xen_hvm_shared_info;
-
- static void xen_hvm_connect_shared_info(unsigned long pfn)
+ void __ref xen_hvm_init_shared_info(void)
{
+ int cpu;
struct xen_add_to_physmap xatp;
+ static struct shared_info *shared_info_page = 0;
+ if (!shared_info_page)
+ shared_info_page = (struct shared_info *)
+ extend_brk(PAGE_SIZE, PAGE_SIZE);
xatp.domid = DOMID_SELF;
xatp.idx = 0;
xatp.space = XENMAPSPACE_shared_info;
- xatp.gpfn = pfn;
+ xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT;
if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
BUG();
- }
- static void xen_hvm_set_shared_info(struct shared_info *sip)
- {
- int cpu;
-
- HYPERVISOR_shared_info = sip;
+ HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
/* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
* page, we use it in the event channel upcall and in some pvclock
* related functions. We don't need the vcpu_info placement
* optimizations because we don't use any pv_mmu or pv_irq op on
* HVM.
- * When xen_hvm_set_shared_info is run at boot time only vcpu 0 is
- * online but xen_hvm_set_shared_info is run at resume time too and
+ * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is
+ * online but xen_hvm_init_shared_info is run at resume time too and
* in that case multiple vcpus might be online. */
for_each_online_cpu(cpu) {
per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
}
}
- /* Reconnect the shared_info pfn to a mfn */
- void xen_hvm_resume_shared_info(void)
- {
- xen_hvm_connect_shared_info(__pa(xen_hvm_shared_info) >> PAGE_SHIFT);
- }
-
- #ifdef CONFIG_KEXEC
- static struct shared_info *xen_hvm_shared_info_kexec;
- static unsigned long xen_hvm_shared_info_pfn_kexec;
-
- /* Remember a pfn in MMIO space for kexec reboot */
- void __devinit xen_hvm_prepare_kexec(struct shared_info *sip, unsigned long pfn)
- {
- xen_hvm_shared_info_kexec = sip;
- xen_hvm_shared_info_pfn_kexec = pfn;
- }
-
- static void xen_hvm_syscore_shutdown(void)
- {
- struct xen_memory_reservation reservation = {
- .domid = DOMID_SELF,
- .nr_extents = 1,
- };
- unsigned long prev_pfn;
- int rc;
-
- if (!xen_hvm_shared_info_kexec)
- return;
-
- prev_pfn = __pa(xen_hvm_shared_info) >> PAGE_SHIFT;
- set_xen_guest_handle(reservation.extent_start, &prev_pfn);
-
- /* Move pfn to MMIO, disconnects previous pfn from mfn */
- xen_hvm_connect_shared_info(xen_hvm_shared_info_pfn_kexec);
-
- /* Update pointers, following hypercall is also a memory barrier */
- xen_hvm_set_shared_info(xen_hvm_shared_info_kexec);
-
- /* Allocate new mfn for previous pfn */
- do {
- rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
- if (rc == 0)
- msleep(123);
- } while (rc == 0);
-
- /* Make sure the previous pfn is really connected to a (new) mfn */
- BUG_ON(rc != 1);
- }
-
- static struct syscore_ops xen_hvm_syscore_ops = {
- .shutdown = xen_hvm_syscore_shutdown,
- };
- #endif
-
- /* Use a pfn in RAM, may move to MMIO before kexec. */
- static void __init xen_hvm_init_shared_info(void)
- {
- /* Remember pointer for resume */
- xen_hvm_shared_info = extend_brk(PAGE_SIZE, PAGE_SIZE);
- xen_hvm_connect_shared_info(__pa(xen_hvm_shared_info) >> PAGE_SHIFT);
- xen_hvm_set_shared_info(xen_hvm_shared_info);
- }
-
+ #ifdef CONFIG_XEN_PVHVM
static void __init init_hvm_pv_info(void)
{
int major, minor;
init_hvm_pv_info();
xen_hvm_init_shared_info();
- #ifdef CONFIG_KEXEC
- register_syscore_ops(&xen_hvm_syscore_ops);
- #endif
if (xen_feature(XENFEAT_hvm_callback_vector))
xen_have_vector_callback = 1;
projects / firefly-linux-kernel-4.4.55.git / commitdiff