* FAILED: patch "[PATCH] KVM: SVM: restore host save area from assembly" failed to apply to 5.10-stable tree
@ 2022-11-14 11:00 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2022-11-14 11:00 UTC (permalink / raw)
To: pbonzini, andrew.cooper3, nathan, seanjc; +Cc: stable
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
Possible dependencies:
e287bd005ad9 ("KVM: SVM: restore host save area from assembly")
e61ab42de874 ("KVM: SVM: move guest vmsave/vmload back to assembly")
73412dfeea72 ("KVM: SVM: do not allocate struct svm_cpu_data dynamically")
181d0fb0bb02 ("KVM: SVM: remove dead field from struct svm_cpu_data")
f6d58266d731 ("KVM: SVM: retrieve VMCB from assembly")
f7ef280132f9 ("KVM: SVM: adjust register allocation for __svm_vcpu_run()")
16fdc1de169e ("KVM: SVM: replace regs argument of __svm_vcpu_run() with vcpu_svm")
debc5a1ec0d1 ("KVM: x86: use a separate asm-offsets.c file")
bb06650634d3 ("KVM: VMX: Convert launched argument to flags")
8bd200d23ec4 ("KVM: VMX: Flatten __vmx_vcpu_run()")
527a534c7326 ("x86/tdx: Provide common base for SEAMCALL and TDCALL C wrappers")
59bd54a84d15 ("x86/tdx: Detect running as a TDX guest in early boot")
1ebdbeb03efe ("Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e287bd005ad9d85dd6271dd795d3ecfb6bca46ad Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Mon, 7 Nov 2022 03:49:59 -0500
Subject: [PATCH] KVM: SVM: restore host save area from assembly
Allow access to the percpu area via the GS segment base, which is
needed in order to access the saved host spec_ctrl value. In linux-next
FILL_RETURN_BUFFER also needs to access percpu data.
For simplicity, the physical address of the save area is added to struct
svm_cpu_data.
Cc: stable@vger.kernel.org
Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Analyzed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/kvm-asm-offsets.c b/arch/x86/kvm/kvm-asm-offsets.c
index f83e88b85bf2..1b805cd24d66 100644
--- a/arch/x86/kvm/kvm-asm-offsets.c
+++ b/arch/x86/kvm/kvm-asm-offsets.c
@@ -18,6 +18,7 @@ static void __used common(void)
OFFSET(SVM_current_vmcb, vcpu_svm, current_vmcb);
OFFSET(SVM_vmcb01, vcpu_svm, vmcb01);
OFFSET(KVM_VMCB_pa, kvm_vmcb_info, pa);
+ OFFSET(SD_save_area_pa, svm_cpu_data, save_area_pa);
}
if (IS_ENABLED(CONFIG_KVM_INTEL)) {
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 4e3a47eb5002..469c1b5617af 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -592,7 +592,7 @@ static int svm_hardware_enable(void)
wrmsrl(MSR_EFER, efer | EFER_SVME);
- wrmsrl(MSR_VM_HSAVE_PA, __sme_page_pa(sd->save_area));
+ wrmsrl(MSR_VM_HSAVE_PA, sd->save_area_pa);
if (static_cpu_has(X86_FEATURE_TSCRATEMSR)) {
/*
@@ -648,6 +648,7 @@ static void svm_cpu_uninit(int cpu)
kfree(sd->sev_vmcbs);
__free_page(sd->save_area);
+ sd->save_area_pa = 0;
sd->save_area = NULL;
}
@@ -665,6 +666,7 @@ static int svm_cpu_init(int cpu)
if (ret)
goto free_save_area;
+ sd->save_area_pa = __sme_page_pa(sd->save_area);
return 0;
free_save_area:
@@ -1450,7 +1452,7 @@ static void svm_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
* Save additional host state that will be restored on VMEXIT (sev-es)
* or subsequent vmload of host save area.
*/
- vmsave(__sme_page_pa(sd->save_area));
+ vmsave(sd->save_area_pa);
if (sev_es_guest(vcpu->kvm)) {
struct sev_es_save_area *hostsa;
hostsa = (struct sev_es_save_area *)(page_address(sd->save_area) + 0x400);
@@ -3905,14 +3907,10 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu)
guest_state_enter_irqoff();
- if (sev_es_guest(vcpu->kvm)) {
+ if (sev_es_guest(vcpu->kvm))
__svm_sev_es_vcpu_run(svm);
- } else {
- struct svm_cpu_data *sd = per_cpu_ptr(&svm_data, vcpu->cpu);
-
+ else
__svm_vcpu_run(svm);
- vmload(__sme_page_pa(sd->save_area));
- }
guest_state_exit_irqoff();
}
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 2af6a71126c1..83955a4e520e 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -287,6 +287,8 @@ struct svm_cpu_data {
struct kvm_ldttss_desc *tss_desc;
struct page *save_area;
+ unsigned long save_area_pa;
+
struct vmcb *current_vmcb;
/* index = sev_asid, value = vmcb pointer */
diff --git a/arch/x86/kvm/svm/svm_ops.h b/arch/x86/kvm/svm/svm_ops.h
index 9430d6437c9f..36c8af87a707 100644
--- a/arch/x86/kvm/svm/svm_ops.h
+++ b/arch/x86/kvm/svm/svm_ops.h
@@ -61,9 +61,4 @@ static __always_inline void vmsave(unsigned long pa)
svm_asm1(vmsave, "a" (pa), "memory");
}
-static __always_inline void vmload(unsigned long pa)
-{
- svm_asm1(vmload, "a" (pa), "memory");
-}
-
#endif /* __KVM_X86_SVM_OPS_H */
diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
index 5bc2ed7d79c0..57440acfc73e 100644
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -49,6 +49,14 @@ SYM_FUNC_START(__svm_vcpu_run)
#endif
push %_ASM_BX
+ /*
+ * Save variables needed after vmexit on the stack, in inverse
+ * order compared to when they are needed.
+ */
+
+ /* Needed to restore access to percpu variables. */
+ __ASM_SIZE(push) PER_CPU_VAR(svm_data + SD_save_area_pa)
+
/* Save @svm. */
push %_ASM_ARG1
@@ -124,6 +132,11 @@ SYM_FUNC_START(__svm_vcpu_run)
5: vmsave %_ASM_AX
6:
+ /* Restores GSBASE among other things, allowing access to percpu data. */
+ pop %_ASM_AX
+7: vmload %_ASM_AX
+8:
+
#ifdef CONFIG_RETPOLINE
/* IMPORTANT: Stuff the RSB immediately after VM-Exit, before RET! */
FILL_RETURN_BUFFER %_ASM_AX, RSB_CLEAR_LOOPS, X86_FEATURE_RETPOLINE
@@ -187,10 +200,14 @@ SYM_FUNC_START(__svm_vcpu_run)
50: cmpb $0, kvm_rebooting
jne 6b
ud2
+70: cmpb $0, kvm_rebooting
+ jne 8b
+ ud2
_ASM_EXTABLE(1b, 10b)
_ASM_EXTABLE(3b, 30b)
_ASM_EXTABLE(5b, 50b)
+ _ASM_EXTABLE(7b, 70b)
SYM_FUNC_END(__svm_vcpu_run)
^ permalink raw reply related [flat|nested] only message in thread
only message in thread, other threads:[~2022-11-14 11:01 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-14 11:00 FAILED: patch "[PATCH] KVM: SVM: restore host save area from assembly" failed to apply to 5.10-stable tree gregkh
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).