From fae1a3e775cca8c3a9e0eb34443b310871a15a92 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 21 Dec 2017 00:49:14 +0100 Subject: kvm: x86: fix RSM when PCID is non-zero rsm_load_state_64() and rsm_enter_protected_mode() load CR3, then CR4 & ~PCIDE, then CR0, then CR4. However, setting CR4.PCIDE fails if CR3[11:0] != 0. It's probably easier in the long run to replace rsm_enter_protected_mode() with an emulator callback that sets all the special registers (like KVM_SET_SREGS would do). For now, set the PCID field of CR3 only after CR4.PCIDE is 1. Reported-by: Laszlo Ersek Tested-by: Laszlo Ersek Fixes: 660a5d517aaab9187f93854425c4c63f4a09195c Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-) (limited to 'arch/x86/kvm/emulate.c') diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index abe74f779f9d..b514b2b2845a 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2390,9 +2390,21 @@ static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, u64 smbase, int n) } static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt, - u64 cr0, u64 cr4) + u64 cr0, u64 cr3, u64 cr4) { int bad; + u64 pcid; + + /* In order to later set CR4.PCIDE, CR3[11:0] must be zero. */ + pcid = 0; + if (cr4 & X86_CR4_PCIDE) { + pcid = cr3 & 0xfff; + cr3 &= ~0xfff; + } + + bad = ctxt->ops->set_cr(ctxt, 3, cr3); + if (bad) + return X86EMUL_UNHANDLEABLE; /* * First enable PAE, long mode needs it before CR0.PG = 1 is set. @@ -2411,6 +2423,12 @@ static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt, bad = ctxt->ops->set_cr(ctxt, 4, cr4); if (bad) return X86EMUL_UNHANDLEABLE; + if (pcid) { + bad = ctxt->ops->set_cr(ctxt, 3, cr3 | pcid); + if (bad) + return X86EMUL_UNHANDLEABLE; + } + } return X86EMUL_CONTINUE; @@ -2421,11 +2439,11 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, u64 smbase) struct desc_struct desc; struct desc_ptr dt; u16 selector; - u32 val, cr0, cr4; + u32 val, cr0, cr3, cr4; int i; cr0 = GET_SMSTATE(u32, smbase, 0x7ffc); - ctxt->ops->set_cr(ctxt, 3, GET_SMSTATE(u32, smbase, 0x7ff8)); + cr3 = GET_SMSTATE(u32, smbase, 0x7ff8); ctxt->eflags = GET_SMSTATE(u32, smbase, 0x7ff4) | X86_EFLAGS_FIXED; ctxt->_eip = GET_SMSTATE(u32, smbase, 0x7ff0); @@ -2467,14 +2485,14 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, u64 smbase) ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smbase, 0x7ef8)); - return rsm_enter_protected_mode(ctxt, cr0, cr4); + return rsm_enter_protected_mode(ctxt, cr0, cr3, cr4); } static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase) { struct desc_struct desc; struct desc_ptr dt; - u64 val, cr0, cr4; + u64 val, cr0, cr3, cr4; u32 base3; u16 selector; int i, r; @@ -2491,7 +2509,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase) ctxt->ops->set_dr(ctxt, 7, (val & DR7_VOLATILE) | DR7_FIXED_1); cr0 = GET_SMSTATE(u64, smbase, 0x7f58); - ctxt->ops->set_cr(ctxt, 3, GET_SMSTATE(u64, smbase, 0x7f50)); + cr3 = GET_SMSTATE(u64, smbase, 0x7f50); cr4 = GET_SMSTATE(u64, smbase, 0x7f48); ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smbase, 0x7f00)); val = GET_SMSTATE(u64, smbase, 0x7ed0); @@ -2519,7 +2537,7 @@ 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); + r = rsm_enter_protected_mode(ctxt, cr0, cr3, cr4); if (r != X86EMUL_CONTINUE) return r; -- cgit v1.2.3 From 1a29b5b7f347a1a9230c1e0af5b37e3e571588ab Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 25 Jan 2018 10:58:13 +0100 Subject: KVM: x86: Make indirect calls in emulator speculation safe Replace the indirect calls with CALL_NOSPEC. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Reviewed-by: David Woodhouse Cc: Andrea Arcangeli Cc: Andi Kleen Cc: Ashok Raj Cc: Greg KH Cc: Jun Nakajima Cc: David Woodhouse Cc: Linus Torvalds Cc: rga@amazon.de Cc: Dave Hansen Cc: Asit Mallick Cc: Andy Lutomirski Cc: Josh Poimboeuf Cc: Jason Baron Cc: Paolo Bonzini Cc: Dan Williams Cc: Arjan Van De Ven Cc: Tim Chen Link: https://lkml.kernel.org/r/20180125095843.595615683@infradead.org --- arch/x86/kvm/emulate.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'arch/x86/kvm/emulate.c') diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index d90cdc77e077..453d8c990108 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -25,6 +25,7 @@ #include #include #include +#include #include "x86.h" #include "tss.h" @@ -1021,8 +1022,8 @@ static __always_inline u8 test_cc(unsigned int condition, unsigned long flags) void (*fop)(void) = (void *)em_setcc + 4 * (condition & 0xf); flags = (flags & EFLAGS_MASK) | X86_EFLAGS_IF; - asm("push %[flags]; popf; call *%[fastop]" - : "=a"(rc) : [fastop]"r"(fop), [flags]"r"(flags)); + asm("push %[flags]; popf; " CALL_NOSPEC + : "=a"(rc) : [thunk_target]"r"(fop), [flags]"r"(flags)); return rc; } @@ -5305,9 +5306,9 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)) if (!(ctxt->d & ByteOp)) fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE; - asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n" + asm("push %[flags]; popf; " CALL_NOSPEC " ; pushf; pop %[flags]\n" : "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags), - [fastop]"+S"(fop), ASM_CALL_CONSTRAINT + [thunk_target]"+S"(fop), ASM_CALL_CONSTRAINT : "c"(ctxt->src2.val)); ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK); -- cgit v1.2.3