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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 1/6] x86/vmx: Simplfy the default cases in vmx_msr_{read, write}_intercept()
The default case of vmx_msr_write_intercept() in particular is very tangled.
First of all, fold long_mode_do_msr_{read,write}() into their callers. These
functions were split out in the past because of the 32bit build of Xen, but it
is unclear why the cases weren't simply #ifdef'd in place.
Next, invert the vmx_write_guest_msr()/is_last_branch_msr() logic to break if
the condition is satisfied, rather than nesting if it wasn't. This allows the
wrmsr_hypervisor_regs() call to be un-nested with respect to the other default
logic.
No practical difference from a guests point of view.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Jun Nakajima <jun.nakajima@xxxxxxxxx>
CC: Kevin Tian <kevin.tian@xxxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
---
xen/arch/x86/hvm/vmx/vmx.c | 214 ++++++++++++++++++---------------------------
1 file changed, 86 insertions(+), 128 deletions(-)
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 8f6d87b..e1e4f17 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -482,102 +482,6 @@ static void vmx_vcpu_destroy(struct vcpu *v)
passive_domain_destroy(v);
}
-static int long_mode_do_msr_read(unsigned int msr, uint64_t *msr_content)
-{
- struct vcpu *v = current;
-
- switch ( msr )
- {
- case MSR_FS_BASE:
- __vmread(GUEST_FS_BASE, msr_content);
- break;
-
- case MSR_GS_BASE:
- __vmread(GUEST_GS_BASE, msr_content);
- break;
-
- case MSR_SHADOW_GS_BASE:
- rdmsrl(MSR_SHADOW_GS_BASE, *msr_content);
- break;
-
- case MSR_STAR:
- *msr_content = v->arch.hvm_vmx.star;
- break;
-
- case MSR_LSTAR:
- *msr_content = v->arch.hvm_vmx.lstar;
- break;
-
- case MSR_CSTAR:
- *msr_content = v->arch.hvm_vmx.cstar;
- break;
-
- case MSR_SYSCALL_MASK:
- *msr_content = v->arch.hvm_vmx.sfmask;
- break;
-
- default:
- return X86EMUL_UNHANDLEABLE;
- }
-
- HVM_DBG_LOG(DBG_LEVEL_MSR, "msr %#x content %#"PRIx64, msr, *msr_content);
-
- return X86EMUL_OKAY;
-}
-
-static int long_mode_do_msr_write(unsigned int msr, uint64_t msr_content)
-{
- struct vcpu *v = current;
-
- HVM_DBG_LOG(DBG_LEVEL_MSR, "msr %#x content %#"PRIx64, msr, msr_content);
-
- switch ( msr )
- {
- case MSR_FS_BASE:
- case MSR_GS_BASE:
- case MSR_SHADOW_GS_BASE:
- if ( !is_canonical_address(msr_content) )
- return X86EMUL_EXCEPTION;
-
- if ( msr == MSR_FS_BASE )
- __vmwrite(GUEST_FS_BASE, msr_content);
- else if ( msr == MSR_GS_BASE )
- __vmwrite(GUEST_GS_BASE, msr_content);
- else
- wrmsrl(MSR_SHADOW_GS_BASE, msr_content);
-
- break;
-
- case MSR_STAR:
- v->arch.hvm_vmx.star = msr_content;
- wrmsrl(MSR_STAR, msr_content);
- break;
-
- case MSR_LSTAR:
- if ( !is_canonical_address(msr_content) )
- return X86EMUL_EXCEPTION;
- v->arch.hvm_vmx.lstar = msr_content;
- wrmsrl(MSR_LSTAR, msr_content);
- break;
-
- case MSR_CSTAR:
- if ( !is_canonical_address(msr_content) )
- return X86EMUL_EXCEPTION;
- v->arch.hvm_vmx.cstar = msr_content;
- break;
-
- case MSR_SYSCALL_MASK:
- v->arch.hvm_vmx.sfmask = msr_content;
- wrmsrl(MSR_SYSCALL_MASK, msr_content);
- break;
-
- default:
- return X86EMUL_UNHANDLEABLE;
- }
-
- return X86EMUL_OKAY;
-}
-
/*
* To avoid MSR save/restore at every VM exit/entry time, we restore
* the x86_64 specific MSRs at domain switch time. Since these MSRs
@@ -2894,6 +2798,35 @@ static int vmx_msr_read_intercept(unsigned int msr,
uint64_t *msr_content)
case MSR_IA32_SYSENTER_EIP:
__vmread(GUEST_SYSENTER_EIP, msr_content);
break;
+
+ case MSR_FS_BASE:
+ __vmread(GUEST_FS_BASE, msr_content);
+ break;
+
+ case MSR_GS_BASE:
+ __vmread(GUEST_GS_BASE, msr_content);
+ break;
+
+ case MSR_SHADOW_GS_BASE:
+ rdmsrl(MSR_SHADOW_GS_BASE, *msr_content);
+ break;
+
+ case MSR_STAR:
+ *msr_content = curr->arch.hvm_vmx.star;
+ break;
+
+ case MSR_LSTAR:
+ *msr_content = curr->arch.hvm_vmx.lstar;
+ break;
+
+ case MSR_CSTAR:
+ *msr_content = curr->arch.hvm_vmx.cstar;
+ break;
+
+ case MSR_SYSCALL_MASK:
+ *msr_content = curr->arch.hvm_vmx.sfmask;
+ break;
+
case MSR_IA32_DEBUGCTLMSR:
__vmread(GUEST_IA32_DEBUGCTL, msr_content);
break;
@@ -2928,14 +2861,6 @@ static int vmx_msr_read_intercept(unsigned int msr,
uint64_t *msr_content)
default:
if ( passive_domain_do_rdmsr(msr, msr_content) )
goto done;
- switch ( long_mode_do_msr_read(msr, msr_content) )
- {
- case X86EMUL_EXCEPTION:
- return X86EMUL_EXCEPTION;
-
- case X86EMUL_OKAY:
- goto done;
- }
if ( vmx_read_guest_msr(msr, msr_content) == 0 )
break;
@@ -3090,6 +3015,45 @@ static int vmx_msr_write_intercept(unsigned int msr,
uint64_t msr_content)
goto gp_fault;
__vmwrite(GUEST_SYSENTER_EIP, msr_content);
break;
+
+ case MSR_FS_BASE:
+ case MSR_GS_BASE:
+ case MSR_SHADOW_GS_BASE:
+ if ( !is_canonical_address(msr_content) )
+ goto gp_fault;
+
+ if ( msr == MSR_FS_BASE )
+ __vmwrite(GUEST_FS_BASE, msr_content);
+ else if ( msr == MSR_GS_BASE )
+ __vmwrite(GUEST_GS_BASE, msr_content);
+ else
+ wrmsrl(MSR_SHADOW_GS_BASE, msr_content);
+
+ break;
+
+ case MSR_STAR:
+ v->arch.hvm_vmx.star = msr_content;
+ wrmsrl(MSR_STAR, msr_content);
+ break;
+
+ case MSR_LSTAR:
+ if ( !is_canonical_address(msr_content) )
+ goto gp_fault;
+ v->arch.hvm_vmx.lstar = msr_content;
+ wrmsrl(MSR_LSTAR, msr_content);
+ break;
+
+ case MSR_CSTAR:
+ if ( !is_canonical_address(msr_content) )
+ goto gp_fault;
+ v->arch.hvm_vmx.cstar = msr_content;
+ break;
+
+ case MSR_SYSCALL_MASK:
+ v->arch.hvm_vmx.sfmask = msr_content;
+ wrmsrl(MSR_SYSCALL_MASK, msr_content);
+ break;
+
case MSR_IA32_DEBUGCTLMSR: {
int i, rc = 0;
uint64_t supported = IA32_DEBUGCTLMSR_LBR | IA32_DEBUGCTLMSR_BTF;
@@ -3151,32 +3115,26 @@ static int vmx_msr_write_intercept(unsigned int msr,
uint64_t msr_content)
if ( wrmsr_viridian_regs(msr, msr_content) )
break;
- switch ( long_mode_do_msr_write(msr, msr_content) )
- {
- case X86EMUL_UNHANDLEABLE:
- if ( (vmx_write_guest_msr(msr, msr_content) != 0) &&
- !is_last_branch_msr(msr) )
- switch ( wrmsr_hypervisor_regs(msr, msr_content) )
- {
- case -ERESTART:
- return X86EMUL_RETRY;
- case 0:
- /*
- * Match up with the RDMSR side for now; ultimately this
- * entire case block should go away.
- */
- if ( rdmsr_safe(msr, msr_content) == 0 )
- break;
- goto gp_fault;
- case 1:
- break;
- default:
- goto gp_fault;
- }
+ if ( vmx_write_guest_msr(msr, msr_content) == 0 ||
+ is_last_branch_msr(msr) )
break;
- case X86EMUL_EXCEPTION:
- return X86EMUL_EXCEPTION;
+ switch ( wrmsr_hypervisor_regs(msr, msr_content) )
+ {
+ case -ERESTART:
+ return X86EMUL_RETRY;
+ case 0:
+ /*
+ * Match up with the RDMSR side for now; ultimately this
+ * entire case block should go away.
+ */
+ if ( rdmsr_safe(msr, msr_content) == 0 )
+ break;
+ goto gp_fault;
+ case 1:
+ break;
+ default:
+ goto gp_fault;
}
break;
}
--
2.1.4
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