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* [MODERATED] [PATCH v4 4/8] [PATCH v4 4/8] Linux Patch #4
@ 2018-06-23 13:54 konrad.wilk
  2018-06-27 16:39 ` [MODERATED] " Borislav Petkov
  0 siblings, 1 reply; 2+ messages in thread
From: konrad.wilk @ 2018-06-23 13:54 UTC (permalink / raw)
  To: speck

There is no semantic change but with this change we can allow an
unbalanced amount of MSRs to be loaded on VMEXIT and VMENTER.

That is the number of MSRs to save or restore on VMEXIT or VMENTER may
be different.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/kvm/vmx.c | 65 +++++++++++++++++++++++++++++-------------------------
 1 file changed, 35 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a51418429165..3649bf3b3b82 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -763,6 +763,11 @@ static inline int pi_test_sn(struct pi_desc *pi_desc)
 			(unsigned long *)&pi_desc->control);
 }
 
+struct vmx_msrs {
+	unsigned nr;
+	struct vmx_msr_entry val[NR_AUTOLOAD_MSRS];
+};
+
 struct vcpu_vmx {
 	struct kvm_vcpu       vcpu;
 	unsigned long         host_rsp;
@@ -796,9 +801,8 @@ struct vcpu_vmx {
 	struct loaded_vmcs   *loaded_vmcs;
 	bool                  __launched; /* temporary, used in vmx_vcpu_run */
 	struct msr_autoload {
-		unsigned nr;
-		struct vmx_msr_entry guest[NR_AUTOLOAD_MSRS];
-		struct vmx_msr_entry host[NR_AUTOLOAD_MSRS];
+		struct vmx_msrs guest;
+		struct vmx_msrs host;
 	} msr_autoload;
 	struct {
 		int           loaded;
@@ -2395,18 +2399,18 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
 		}
 		break;
 	}
-
-	for (i = 0; i < m->nr; ++i)
-		if (m->guest[i].index == msr)
+	for (i = 0; i < m->guest.nr; ++i)
+		if (m->guest.val[i].index == msr)
 			break;
 
-	if (i == m->nr)
+	if (i == m->guest.nr)
 		return;
-	--m->nr;
-	m->guest[i] = m->guest[m->nr];
-	m->host[i] = m->host[m->nr];
-	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->nr);
-	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->nr);
+	--m->guest.nr;
+	--m->host.nr;
+	m->guest.val[i] = m->guest.val[m->guest.nr];
+	m->host.val[i] = m->host.val[m->host.nr];
+	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);
+	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr);
 }
 
 static void add_atomic_switch_msr_special(struct vcpu_vmx *vmx,
@@ -2458,24 +2462,25 @@ static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
 		wrmsrl(MSR_IA32_PEBS_ENABLE, 0);
 	}
 
-	for (i = 0; i < m->nr; ++i)
-		if (m->guest[i].index == msr)
+	for (i = 0; i < m->guest.nr; ++i)
+		if (m->guest.val[i].index == msr)
 			break;
 
 	if (i == NR_AUTOLOAD_MSRS) {
 		printk_once(KERN_WARNING "Not enough msr switch entries. "
 				"Can't add msr %x\n", msr);
 		return;
-	} else if (i == m->nr) {
-		++m->nr;
-		vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->nr);
-		vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->nr);
+	} else if (i == m->guest.nr) {
+		++m->guest.nr;
+		++m->host.nr;
+		vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);
+		vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr);
 	}
 
-	m->guest[i].index = msr;
-	m->guest[i].value = guest_val;
-	m->host[i].index = msr;
-	m->host[i].value = host_val;
+	m->guest.val[i].index = msr;
+	m->guest.val[i].value = guest_val;
+	m->host.val[i].index = msr;
+	m->host.val[i].value = host_val;
 }
 
 static bool update_transition_efer(struct vcpu_vmx *vmx, int efer_offset)
@@ -6284,9 +6289,9 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx)
 
 	vmcs_write32(VM_EXIT_MSR_STORE_COUNT, 0);
 	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, 0);
-	vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host));
+	vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host.val));
 	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, 0);
-	vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest));
+	vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest.val));
 
 	if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT)
 		vmcs_write64(GUEST_IA32_PAT, vmx->vcpu.arch.pat);
@@ -11286,10 +11291,10 @@ static void prepare_vmcs02_full(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 	 * Set the MSR load/store lists to match L0's settings.
 	 */
 	vmcs_write32(VM_EXIT_MSR_STORE_COUNT, 0);
-	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.nr);
-	vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host));
-	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.nr);
-	vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest));
+	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.host.nr);
+	vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host.val));
+	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr);
+	vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest.val));
 
 	set_cr4_guest_host_mask(vmx);
 
@@ -12393,8 +12398,8 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
 	vmx_segment_cache_clear(vmx);
 
 	/* Update any VMCS fields that might have changed while L2 ran */
-	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.nr);
-	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.nr);
+	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.host.nr);
+	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr);
 	vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset);
 	if (vmx->hv_deadline_tsc == -1)
 		vmcs_clear_bits(PIN_BASED_VM_EXEC_CONTROL,
-- 
2.14.3

^ permalink raw reply related	[flat|nested] 2+ messages in thread
* [MODERATED] Re: [PATCH v4 4/8] [PATCH v4 4/8] Linux Patch #4
  2018-06-23 13:54 [MODERATED] [PATCH v4 4/8] [PATCH v4 4/8] Linux Patch #4 konrad.wilk
@ 2018-06-27 16:39 ` Borislav Petkov
  0 siblings, 0 replies; 2+ messages in thread
From: Borislav Petkov @ 2018-06-27 16:39 UTC (permalink / raw)
  To: speck

On Sat, Jun 23, 2018 at 09:54:18AM -0400, speck for konrad.wilk_at_oracle.com wrote:
> x86/KVM/VMX: Split the VMX MSR LOAD structures to have an host/guest numbers.
> 
> There is no semantic change but with this change we can allow an
> unbalanced amount of MSRs to be loaded on VMEXIT and VMENTER.
> 
> That is the number of MSRs to save or restore on VMEXIT or VMENTER may
> be different.

This commit message could use some big picture blurb for outsiders like
me to explain why we're doing this...

> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
>  arch/x86/kvm/vmx.c | 65 +++++++++++++++++++++++++++++-------------------------
>  1 file changed, 35 insertions(+), 30 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index a51418429165..3649bf3b3b82 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -763,6 +763,11 @@ static inline int pi_test_sn(struct pi_desc *pi_desc)
>  			(unsigned long *)&pi_desc->control);
>  }
>  
> +struct vmx_msrs {
> +	unsigned nr;

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
#36: FILE: arch/x86/kvm/vmx.c:767:
+       unsigned nr;

Even checkpatch is sometimes right. :)

> +	struct vmx_msr_entry val[NR_AUTOLOAD_MSRS];
> +};
> +

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
-- 

^ permalink raw reply	[flat|nested] 2+ messages in thread
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2018-06-23 13:54 [MODERATED] [PATCH v4 4/8] [PATCH v4 4/8] Linux Patch #4 konrad.wilk
2018-06-27 16:39 ` [MODERATED] " Borislav Petkov

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