KVM: x86: fix RSM into 64-bit protected mode (b10d92a5) · Commits · 戴 / test

In order to get into 64-bit protected mode, you need to enable paging while EFER.LMA=1. For this to work, CS.L must be 0. Currently, we load the segments before CR0 and CR4, which means that if RSM returns into 64-bit protected mode CS.L is already 1 and everything breaks. Luckily, CS.L=0 is always the case when executing RSM, because it is forbidden to execute RSM from 64-bit protected mode. Hence it is enough to load CR0 and CR4 first, and only then the segments. Fixes: Cc: stable@vger.kernel.org Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/emulate.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -2418,7 +2418,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
		u64 val, cr0, cr4;
		u32 base3;
		u16 selector;
		int i;
		int i, r;

		for (i = 0; i < 16; i++)
		reg_write(ctxt, i) = GET_SMSTATE(u64, smbase, 0x7ff8 - i 8);
		@@ -2460,13 +2460,17 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
		dt.address = GET_SMSTATE(u64, smbase, 0x7e68);
		ctxt->ops->set_gdt(ctxt, &dt);

		r = rsm_enter_protected_mode(ctxt, cr0, cr4);
		if (r != X86EMUL_CONTINUE)
		return r;

		for (i = 0; i < 6; i++) {
		int r = rsm_load_seg_64(ctxt, smbase, i);
		r = rsm_load_seg_64(ctxt, smbase, i);
		if (r != X86EMUL_CONTINUE)
		return r;
		}

		return rsm_enter_protected_mode(ctxt, cr0, cr4);
		return X86EMUL_CONTINUE;
		}

		static int em_rsm(struct x86_emulate_ctxt *ctxt)

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