diff mbox series

[v4,2/7] hyperv: SVM enlightened TLB flush support flag

Message ID cce3e52fde732ccdc7a34d2eb1e2d59917e4e5e0.1619556430.git.viremana@linux.microsoft.com (mailing list archive)
State New, archived
Headers show
Series Hyper-V nested virt enlightenments for SVM | expand

Commit Message

Vineeth Pillai April 27, 2021, 8:54 p.m. UTC
Bit 22 of HYPERV_CPUID_FEATURES.EDX is specific to SVM and specifies
support for enlightened TLB flush. With this enlightenment enabled,
ASID invalidations flushes only gva->hpa entries. To flush TLB entries
derived from NPT, hypercalls should be used
(HvFlushGuestPhysicalAddressSpace or HvFlushGuestPhysicalAddressList)

Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
---
 arch/x86/include/asm/hyperv-tlfs.h | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Wei Liu April 28, 2021, 1:47 p.m. UTC | #1
On Tue, Apr 27, 2021 at 08:54:51PM +0000, Vineeth Pillai wrote:
> Bit 22 of HYPERV_CPUID_FEATURES.EDX is specific to SVM and specifies
> support for enlightened TLB flush. With this enlightenment enabled,
> ASID invalidations flushes only gva->hpa entries. To flush TLB entries
> derived from NPT, hypercalls should be used
> (HvFlushGuestPhysicalAddressSpace or HvFlushGuestPhysicalAddressList)
> 
> Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>

Acked-by: Wei Liu <wei.liu@kernel.org>
diff mbox series

Patch

diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 606f5cc579b2..005bf14d0449 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -133,6 +133,15 @@ 
 #define HV_X64_NESTED_GUEST_MAPPING_FLUSH		BIT(18)
 #define HV_X64_NESTED_MSR_BITMAP			BIT(19)
 
+/*
+ * This is specific to AMD and specifies that enlightened TLB flush is
+ * supported. If guest opts in to this feature, ASID invalidations only
+ * flushes gva -> hpa mapping entries. To flush the TLB entries derived
+ * from NPT, hypercalls should be used (HvFlushGuestPhysicalAddressSpace
+ * or HvFlushGuestPhysicalAddressList).
+ */
+#define HV_X64_NESTED_ENLIGHTENED_TLB			BIT(22)
+
 /* HYPERV_CPUID_ISOLATION_CONFIG.EAX bits. */
 #define HV_PARAVISOR_PRESENT				BIT(0)