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Wanpeng Li
ed52870f46
The below test case can cause infinite loop in kvm when ept=0.
#include <unistd.h>
#include <sys/syscall.h>
#include <string.h>
#include <stdint.h>
#include <linux/kvm.h>
#include <fcntl.h>
#include <sys/ioctl.h>
long r[5];
int main()
{
r[2] = open("/dev/kvm", O_RDONLY);
r[3] = ioctl(r[2], KVM_CREATE_VM, 0);
r[4] = ioctl(r[3], KVM_CREATE_VCPU, 7);
ioctl(r[4], KVM_RUN, 0);
}
It doesn't setup the memory regions, mmu_alloc_shadow/direct_roots() in
kvm return 1 when kvm fails to allocate root page table which can result
in beblow infinite loop:
vcpu_run() {
for (;;) {
r = vcpu_enter_guest()::kvm_mmu_reload() returns 1
if (r <= 0)
break;
if (need_resched())
cond_resched();
}
}
This patch fixes it by returning -ENOSPC when there is no available kvm mmu
page for root page table.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 26eeb53cf0 (KVM: MMU: Bail out immediately if there is no available mmu page)
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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