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KVM: x86: manually unroll bad_mt_xwr loop
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The loop is computing one of two constants, it can be simpler to write
everything inline.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Paolo Bonzini committed Oct 16, 2015
1 parent 089d7b6 commit 951f9fd
Showing 1 changed file with 10 additions and 8 deletions.
18 changes: 10 additions & 8 deletions arch/x86/kvm/mmu.c
Original file line number Diff line number Diff line change
Expand Up @@ -3706,7 +3706,7 @@ static void
__reset_rsvds_bits_mask_ept(struct rsvd_bits_validate *rsvd_check,
int maxphyaddr, bool execonly)
{
int pte;
u64 bad_mt_xwr;

rsvd_check->rsvd_bits_mask[0][3] =
rsvd_bits(maxphyaddr, 51) | rsvd_bits(3, 7);
Expand All @@ -3724,14 +3724,16 @@ __reset_rsvds_bits_mask_ept(struct rsvd_bits_validate *rsvd_check,
rsvd_bits(maxphyaddr, 51) | rsvd_bits(12, 20);
rsvd_check->rsvd_bits_mask[1][0] = rsvd_check->rsvd_bits_mask[0][0];

for (pte = 0; pte < 64; pte++) {
int rwx_bits = pte & 7;
int mt = pte >> 3;
if (mt == 0x2 || mt == 0x3 || mt == 0x7 ||
rwx_bits == 0x2 || rwx_bits == 0x6 ||
(rwx_bits == 0x4 && !execonly))
rsvd_check->bad_mt_xwr |= (1ull << pte);
bad_mt_xwr = 0xFFull << (2 * 8); /* bits 3..5 must not be 2 */
bad_mt_xwr |= 0xFFull << (3 * 8); /* bits 3..5 must not be 3 */
bad_mt_xwr |= 0xFFull << (7 * 8); /* bits 3..5 must not be 7 */
bad_mt_xwr |= REPEAT_BYTE(1ull << 2); /* bits 0..2 must not be 010 */
bad_mt_xwr |= REPEAT_BYTE(1ull << 6); /* bits 0..2 must not be 110 */
if (!execonly) {
/* bits 0..2 must not be 100 unless VMX capabilities allow it */
bad_mt_xwr |= REPEAT_BYTE(1ull << 4);
}
rsvd_check->bad_mt_xwr = bad_mt_xwr;
}

static void reset_rsvds_bits_mask_ept(struct kvm_vcpu *vcpu,
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