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From: Pavel Fedin <p.fedin@samsung.com>
To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Marc Zyngier <marc.zyngier@arm.com>
Subject: [PATCH 2/3] KVM: arm64: Correctly handle zero register in system register accesses
Date: Thu, 03 Dec 2015 12:58:41 +0300	[thread overview]
Message-ID: <fff7d3cedc4d6ac0c81b089a4b2d7a992c83fb80.1449136209.git.p.fedin@samsung.com> (raw)
In-Reply-To: <cover.1449136209.git.p.fedin@samsung.com>
In-Reply-To: <cover.1449136209.git.p.fedin@samsung.com>

System register accesses also use zero register for Rt == 31, and
therefore using it will also result in getting SP value instead. This
patch makes them also using new accessors, introduced by the previous
patch.

Additionally, got rid of "massive hack" in kvm_handle_cp_64().

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
---
 arch/arm64/kvm/sys_regs.c            | 79 ++++++++++++++++++++----------------
 arch/arm64/kvm/sys_regs.h            |  4 +-
 arch/arm64/kvm/sys_regs_generic_v8.c |  2 +-
 3 files changed, 46 insertions(+), 39 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 87a64e8..a667228 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -102,7 +102,7 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
 
 	BUG_ON(!p->is_write);
 
-	val = *vcpu_reg(vcpu, p->Rt);
+	val = *p->val;
 	if (!p->is_aarch32) {
 		vcpu_sys_reg(vcpu, r->reg) = val;
 	} else {
@@ -125,13 +125,10 @@ static bool access_gic_sgi(struct kvm_vcpu *vcpu,
 			   const struct sys_reg_params *p,
 			   const struct sys_reg_desc *r)
 {
-	u64 val;
-
 	if (!p->is_write)
 		return read_from_write_only(vcpu, p);
 
-	val = *vcpu_reg(vcpu, p->Rt);
-	vgic_v3_dispatch_sgi(vcpu, val);
+	vgic_v3_dispatch_sgi(vcpu, *p->val);
 
 	return true;
 }
@@ -153,7 +150,7 @@ static bool trap_oslsr_el1(struct kvm_vcpu *vcpu,
 	if (p->is_write) {
 		return ignore_write(vcpu, p);
 	} else {
-		*vcpu_reg(vcpu, p->Rt) = (1 << 3);
+		*p->val = (1 << 3);
 		return true;
 	}
 }
@@ -167,7 +164,7 @@ static bool trap_dbgauthstatus_el1(struct kvm_vcpu *vcpu,
 	} else {
 		u32 val;
 		asm volatile("mrs %0, dbgauthstatus_el1" : "=r" (val));
-		*vcpu_reg(vcpu, p->Rt) = val;
+		*p->val = val;
 		return true;
 	}
 }
@@ -204,13 +201,13 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
 			    const struct sys_reg_desc *r)
 {
 	if (p->is_write) {
-		vcpu_sys_reg(vcpu, r->reg) = *vcpu_reg(vcpu, p->Rt);
+		vcpu_sys_reg(vcpu, r->reg) = *p->val;
 		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
 	} else {
-		*vcpu_reg(vcpu, p->Rt) = vcpu_sys_reg(vcpu, r->reg);
+		*p->val = vcpu_sys_reg(vcpu, r->reg);
 	}
 
-	trace_trap_reg(__func__, r->reg, p->is_write, *vcpu_reg(vcpu, p->Rt));
+	trace_trap_reg(__func__, r->reg, p->is_write, *p->val);
 
 	return true;
 }
@@ -228,7 +225,7 @@ static inline void reg_to_dbg(struct kvm_vcpu *vcpu,
 			      const struct sys_reg_params *p,
 			      u64 *dbg_reg)
 {
-	u64 val = *vcpu_reg(vcpu, p->Rt);
+	u64 val = *p->val;
 
 	if (p->is_32bit) {
 		val &= 0xffffffffUL;
@@ -248,7 +245,7 @@ static inline void dbg_to_reg(struct kvm_vcpu *vcpu,
 	if (p->is_32bit)
 		val &= 0xffffffffUL;
 
-	*vcpu_reg(vcpu, p->Rt) = val;
+	*p->val = val;
 }
 
 static inline bool trap_bvr(struct kvm_vcpu *vcpu,
@@ -697,10 +694,10 @@ static bool trap_dbgidr(struct kvm_vcpu *vcpu,
 		u64 pfr = read_system_reg(SYS_ID_AA64PFR0_EL1);
 		u32 el3 = !!cpuid_feature_extract_field(pfr, ID_AA64PFR0_EL3_SHIFT);
 
-		*vcpu_reg(vcpu, p->Rt) = ((((dfr >> ID_AA64DFR0_WRPS_SHIFT) & 0xf) << 28) |
-					  (((dfr >> ID_AA64DFR0_BRPS_SHIFT) & 0xf) << 24) |
-					  (((dfr >> ID_AA64DFR0_CTX_CMPS_SHIFT) & 0xf) << 20) |
-					  (6 << 16) | (el3 << 14) | (el3 << 12));
+		*p->val = ((((dfr >> ID_AA64DFR0_WRPS_SHIFT) & 0xf) << 28) |
+			   (((dfr >> ID_AA64DFR0_BRPS_SHIFT) & 0xf) << 24) |
+			   (((dfr >> ID_AA64DFR0_CTX_CMPS_SHIFT) & 0xf) << 20) |
+			   (6 << 16) | (el3 << 14) | (el3 << 12));
 		return true;
 	}
 }
@@ -710,10 +707,10 @@ static bool trap_debug32(struct kvm_vcpu *vcpu,
 			 const struct sys_reg_desc *r)
 {
 	if (p->is_write) {
-		vcpu_cp14(vcpu, r->reg) = *vcpu_reg(vcpu, p->Rt);
+		vcpu_cp14(vcpu, r->reg) = *p->val;
 		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
 	} else {
-		*vcpu_reg(vcpu, p->Rt) = vcpu_cp14(vcpu, r->reg);
+		*p->val = vcpu_cp14(vcpu, r->reg);
 	}
 
 	return true;
@@ -740,12 +737,12 @@ static inline bool trap_xvr(struct kvm_vcpu *vcpu,
 		u64 val = *dbg_reg;
 
 		val &= 0xffffffffUL;
-		val |= *vcpu_reg(vcpu, p->Rt) << 32;
+		val |= *p->val << 32;
 		*dbg_reg = val;
 
 		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
 	} else {
-		*vcpu_reg(vcpu, p->Rt) = *dbg_reg >> 32;
+		*p->val = *dbg_reg >> 32;
 	}
 
 	trace_trap_reg(__func__, rd->reg, p->is_write, *dbg_reg);
@@ -1062,12 +1059,14 @@ static int kvm_handle_cp_64(struct kvm_vcpu *vcpu,
 {
 	struct sys_reg_params params;
 	u32 hsr = kvm_vcpu_get_hsr(vcpu);
+	int Rt = (hsr >> 5) & 0xf;
 	int Rt2 = (hsr >> 10) & 0xf;
+	unsigned long val;
 
 	params.is_aarch32 = true;
 	params.is_32bit = false;
 	params.CRm = (hsr >> 1) & 0xf;
-	params.Rt = (hsr >> 5) & 0xf;
+	params.val = &val;
 	params.is_write = ((hsr & 1) == 0);
 
 	params.Op0 = 0;
@@ -1076,15 +1075,12 @@ static int kvm_handle_cp_64(struct kvm_vcpu *vcpu,
 	params.CRn = 0;
 
 	/*
-	 * Massive hack here. Store Rt2 in the top 32bits so we only
-	 * have one register to deal with. As we use the same trap
+	 * Make a 64-bit value out of Rt and Rt2. As we use the same trap
 	 * backends between AArch32 and AArch64, we get away with it.
 	 */
 	if (params.is_write) {
-		u64 val = *vcpu_reg(vcpu, params.Rt);
-		val &= 0xffffffff;
-		val |= *vcpu_reg(vcpu, Rt2) << 32;
-		*vcpu_reg(vcpu, params.Rt) = val;
+		val = vcpu_get_reg(vcpu, Rt) & 0xffffffff;
+		val |= vcpu_get_reg(vcpu, Rt2) << 32;
 	}
 
 	if (!emulate_cp(vcpu, &params, target_specific, nr_specific))
@@ -1095,11 +1091,10 @@ static int kvm_handle_cp_64(struct kvm_vcpu *vcpu,
 	unhandled_cp_access(vcpu, &params);
 
 out:
-	/* Do the opposite hack for the read side */
+	/* Split up the value between registers for the read side */
 	if (!params.is_write) {
-		u64 val = *vcpu_reg(vcpu, params.Rt);
-		val >>= 32;
-		*vcpu_reg(vcpu, Rt2) = val;
+		vcpu_set_reg(vcpu, Rt, val & 0xffffffff);
+		vcpu_set_reg(vcpu, Rt, val >> 32);
 	}
 
 	return 1;
@@ -1118,21 +1113,27 @@ static int kvm_handle_cp_32(struct kvm_vcpu *vcpu,
 {
 	struct sys_reg_params params;
 	u32 hsr = kvm_vcpu_get_hsr(vcpu);
+	int Rt  = (hsr >> 5) & 0xf;
+	unsigned long val = vcpu_get_reg(vcpu, Rt);
 
 	params.is_aarch32 = true;
 	params.is_32bit = true;
 	params.CRm = (hsr >> 1) & 0xf;
-	params.Rt  = (hsr >> 5) & 0xf;
+	params.val = &val;
 	params.is_write = ((hsr & 1) == 0);
 	params.CRn = (hsr >> 10) & 0xf;
 	params.Op0 = 0;
 	params.Op1 = (hsr >> 14) & 0x7;
 	params.Op2 = (hsr >> 17) & 0x7;
 
-	if (!emulate_cp(vcpu, &params, target_specific, nr_specific))
+	if (!emulate_cp(vcpu, &params, target_specific, nr_specific)) {
+		vcpu_set_reg(vcpu, Rt, val);
 		return 1;
-	if (!emulate_cp(vcpu, &params, global, nr_global))
+	}
+	if (!emulate_cp(vcpu, &params, global, nr_global)) {
+		vcpu_set_reg(vcpu, Rt, val);
 		return 1;
+	}
 
 	unhandled_cp_access(vcpu, &params);
 	return 1;
@@ -1230,6 +1231,9 @@ int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run)
 {
 	struct sys_reg_params params;
 	unsigned long esr = kvm_vcpu_get_hsr(vcpu);
+	int Rt = (esr >> 5) & 0x1f;
+	unsigned long val = vcpu_get_reg(vcpu, Rt);
+	int ret;
 
 	trace_kvm_handle_sys_reg(esr);
 
@@ -1240,10 +1244,13 @@ int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run)
 	params.CRn = (esr >> 10) & 0xf;
 	params.CRm = (esr >> 1) & 0xf;
 	params.Op2 = (esr >> 17) & 0x7;
-	params.Rt = (esr >> 5) & 0x1f;
+	params.val = &val;
 	params.is_write = !(esr & 1);
 
-	return emulate_sys_reg(vcpu, &params);
+	ret = emulate_sys_reg(vcpu, &params);
+
+	vcpu_set_reg(vcpu, Rt, val);
+	return ret;
 }
 
 /******************************************************************************
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index eaa324e..3267518 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -28,7 +28,7 @@ struct sys_reg_params {
 	u8	CRn;
 	u8	CRm;
 	u8	Op2;
-	u8	Rt;
+	u_long	*val;
 	bool	is_write;
 	bool	is_aarch32;
 	bool	is_32bit;	/* Only valid if is_aarch32 is true */
@@ -79,7 +79,7 @@ static inline bool ignore_write(struct kvm_vcpu *vcpu,
 static inline bool read_zero(struct kvm_vcpu *vcpu,
 			     const struct sys_reg_params *p)
 {
-	*vcpu_reg(vcpu, p->Rt) = 0;
+	*p->val = 0;
 	return true;
 }
 
diff --git a/arch/arm64/kvm/sys_regs_generic_v8.c b/arch/arm64/kvm/sys_regs_generic_v8.c
index 1e45768..c805576 100644
--- a/arch/arm64/kvm/sys_regs_generic_v8.c
+++ b/arch/arm64/kvm/sys_regs_generic_v8.c
@@ -37,7 +37,7 @@ static bool access_actlr(struct kvm_vcpu *vcpu,
 	if (p->is_write)
 		return ignore_write(vcpu, p);
 
-	*vcpu_reg(vcpu, p->Rt) = vcpu_sys_reg(vcpu, ACTLR_EL1);
+	*p->val = vcpu_sys_reg(vcpu, ACTLR_EL1);
 	return true;
 }
 
-- 
2.4.4

  parent reply	other threads:[~2015-12-03  9:58 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-03  9:58 [PATCH 0/3] KVM: arm64: BUG FIX: Correctly handle zero register transfers Pavel Fedin
2015-12-03  9:58 ` [PATCH 1/3] KVM: arm64: Correctly handle zero register during MMIO Pavel Fedin
2015-12-03 10:51   ` Marc Zyngier
2015-12-03  9:58 ` Pavel Fedin [this message]
2015-12-03 10:49   ` [PATCH 2/3] KVM: arm64: Correctly handle zero register in system register accesses Marc Zyngier
2015-12-03 11:08     ` Pavel Fedin
2015-12-03 11:36       ` Marc Zyngier
2015-12-03 11:55         ` Pavel Fedin
2015-12-03 13:12           ` Marc Zyngier
2015-12-03  9:58 ` [PATCH 3/3] KVM: arm64: Get rid of old vcpu_reg() Pavel Fedin
2015-12-03 10:05 ` [PATCH 0/3] KVM: arm64: BUG FIX: Correctly handle zero register transfers Marc Zyngier
2015-12-03 10:53   ` Pavel Fedin
2015-12-03 11:39     ` Marc Zyngier

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